کنترل بیولوژیک علفهای هرز (Biological control of weeds)

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باسلام، مطالب و مقالات مفیدتون در رابطه با کنترل بیولوژیک علفهای هرز را به فارسی و انگلیسی در این تاپیک قرار دهید. با تشکر.
Developing Biological Control Agents


The development of a successful biological controlagent for a problem non-native plant begins with rigorous procedures for identifying and testing potential organisms:


Lt. Col. Nathaniel Rainey and a student from Interlachen High School release South American planthoppers into the river. Photo by Jasmine Chopra, USACOE-Jacksonville District (2010).



  • [*=left]Discovery and identification: Scientists travel to the target plant's native range in search of its natural enemies. Such field exploration, observation and preliminary testing takes years to complete.
    [*=left]Approval for importation and study: When a candidate organism is identified in its native range, it is reviewed by the United States Department of Agriculture Technical Advisory Group (USDA TAG) before it is imported to the U.S. for further study.
    [*=left]Quarantine studies: Once approval is obtained, the potential biological control agent is imported to the U.S. and placed within a secured quarantine laboratory. There, the organism is raised and extensively studied for host-specificity using appropriate plant species, including related species in other states. Feeding trials and life-history experiments are meant to ensure that the organism will affect only the targeted invading plant species and will not impact native or crop species. This testing often takes several years. Two state-of-the-art quarantine and rearing facilities exist in Florida - one in Ft. Pierce and one in Ft. Lauderdale. To learn more about these facilities, view this article.
    [*=left]Initial field release: If the biological control agent is proven to be host-specific in quarantine and is capable of damaging the pest plant's growth or reproduction, a petition is prepared and submitted to obtain a permit for field release (see here). Once the permit is issued, the organism is released in specific areas to promote establishment. In the field, the biological control agent attacks the target plants. Subsequent generations of the introduced organism suppress the target plants over a long period of time.
    [*=left]Monitoring: From the moment they are imported for quarantine study, all introduced biological control agents are tracked by state and federal scientists. Based on field establishment success and impact data, more releases of the organism may or may not occur. Releases and results are annually recorded with the USDA.
 
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Biological Control Approaches

There are several approaches for using biological control. An approach is chosen after considering the target plant, its habitat, and the management objectives:


  • [*=left]Classical Biological Control: A biological control agent is imported into the U.S. after extensive study. The organism, usually an arthropod or pathogen, is released into its new habitat to attack the target weed. Classical biological control relies on subsequent generations of thebiological control agent to suppress the invading species over a long period of time. The classical approach is the most common method of biological control.
    [*=left]Non-classical Biological Control: This approach involves mass rearing and periodic release of resident biological control agents (native or introduced) to increase their effectiveness. The large number of agents is intended to immediately suppress the target plant. Although this type of biological control is generally used with mass-produced plant pathogens, repeated releases of some insects have occasionally been used to provide season long control of a target weed in areas where it is too cold for the insect to survive the winter.
    [*=left]Adventive (or Fortuitous) Biological Control: Regulation of a pest population by a natural enemy that has arrived from elsewhere without deliberate introduction. Several examples are presented below.
The development of an effective biological control agent requires a significant amount of time and money, involves international cooperation, and may produce unpredictable results. For instance, the biological control agent may fail to reproduce and/or provide the desired control on the target weed.
However, the long-term benefits of an effective biological control agent can far exceed the development costs. The results from a successful biological control agent last longer than most management techniques and it reduces the need for, or amount of, chemical, mechanical, and physical controls. It is believed that successful biological controls save much time and money in aquatic and wetland plant management. During the past 50 years, eighteen biological controls have been evaluated overseas, studied in quarantine, and released in Florida and throughout the southeastern U.S. to control five invasive aquatic plant species.
 

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Alligator weed (​Alternanthera philoxeroides)



Three South American insects were released in the 1960s to control alligator weed, a prolific invasive aquatic plants infesting >80% of Florida's public waters. Because each of these insects stresses alligator weed in different ways, this suite of biological control agents has collectively had excellent results on this formerly problematic plant. Alligator weed is still present in more than 80% of Florida public waters, but at such low levels that it is rarely necessary to control it with other means.







Alligator weed flea beetles (Agasicles hygrophila) were imported from Argentina and first released in Florida in 1964; an example of classical biological control. A member of the Chrysomelidae family, the insect consumes the leaves and parts of the stems of the aquatic form of alligator weed. This insect has been the most effective of the three biological control insects imported to control alligator weed. The U.S. Army Corps of Engineers cancelled all herbicide spraying against alligator weed three years after its introduction. Still, the beetle is less effective in southern Florida because of its sensitivity to climatic extremes.
 

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Alligator weed thrips (Amynothrips andersoni) is native to Argentina and was first released in 1967. It is the least known of the alligator weed biological control insects. Leaf damage by the thrips affects the plant by stunting its growth. This insect is the only one of the three that successfully controls the terrestrial form of alligator weed.

 

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Alligator weed stem borer (Arcola (=Vogtia) malloi) is a small brown moth from Argentina that was released in 1971. The larvae mine inside the stem and cause the plant to wilt and die. This insect is capable of migrating great distances and is the most cold tolerant of the alligator weed insects. Control is most effective when used in conjunction with the alligator weed flea beetle.

 

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Brazilian peppertree (Schinus terebinthifolius)



Adventive Biological Control. The only insect currently causing some damage to Brazilian peppertree in Florida is theadventive torymid wasp, the Brazilian peppertree seed wasp (Megastigmus transvaalensis), which attacks the drupes or seeds. In recent years, this insect has been expanding its range throughout the Brazilian peppertree infested area.Megastigmus transvaalensis was probably introduced accidentally into the USA from Reunion or Mauritius via France in Brazilian peppertree seeds sold as spices in some food shops. In 2001, a detailed two-year study on the distribution and effect of M. transvaalensis on Brazilian peppertree in Florida observed that up to 31% of the drupes were damaged by the wasp during the major winter fruiting period, and up to 76% during the minor spring fruiting phase.
For more information on Brazilian peppertree and biological control, see this Extension publication.
 

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Hydrilla (Hydrilla verticillata)


Worldwide surveys began in 1981 to search for an effective biological control agent for the submersedplant hydrilla. Some of the earliest research studied snails and pathogens, which produced unsatisfactory results. Currently, four insects and one fish have been released to control hydrilla, but only two of these insects are established, and only one is commonly associated with hydrilla in the southeastern U.S. None of the insects have been able to adequately control or stress rapidly increasing hydrilla populations, but the fish has proven to be very effective. During the past 40 years, the the FWC Invasive Plant Management Section (formerly DEP Bureau of Invasive Plant Management) has spent nearly $7.5 million – more than half of its research budget – to evaluate potential biological control candidates and release promising candidates that have passed quarantine regulations. This research has included collaborations with the University of Florida, US Army Corps of Engineers, and the USDA.



The hydrilla tuber weevil (Bagous affinis) was discovered in India and Pakistan and released in the U.S. in 1987. The adult lays eggs on rotting wood and organic matter. After hatching, the larvae burrow into the ground until they find hydrilla tubers. The tuber is destroyed as the insects feed on it. Hydrilla tuber weevils are specific to hydrilla and therefore do not pose a threat to other aquatic plants. The weevils failed to establish because they are only effective during drawdowns and Florida lakes are rarely dry.
 
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The Asian hydrilla leaf-mining fly (Hydrellia pakistanae) was found in India and first released in the U.S. in 1987. The larvae of the Asian hydrilla leaf mining fly, together with the species described below, burrow inside the plant’s leaves. Each insect destroys up to 12 leaves throughout its developmental period. However, hydrilla has not been effectively controlled by these insects. Research efforts are underway to mass-rear them to use in an augmentative biological control strategy.

 

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The Australian hydrilla leaf-mining fly (Hydrellia balciunasi) was found in Australia and first released in the U.S. in 1988. Although it has failed to establish on hydrilla in Florida, a small population of this insect has persisted in East Texas following its release.

 

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The hydrilla stem borer (Bagous hydrillae) was imported from Australia and released in 1991. The larvae burrow into the submerged stems of hydrilla, causing them to fragment. This insect also failed to establish as the stem fragments require a dewatered sandy shoreline for larvae to develop within stem fragments – a rare situation in Florida waters.

 

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The hydrilla miner (Cricotopus lebetis) is a midge that has been associated with hydrilla declines in several Florida locations since 1992. Developing larvae mine the growing shoot tips of hydrilla, which severely injures or kills them. The feeding damage alters the plant’s architecture by preventing new hydrilla stems from reaching the water surface. The life cycle of the hydrilla miner is completed in 1-2 weeks. It is not clear whether the midge is an adventive species or native insect that adapted to hydrilla.


 

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The adventive hydrilla moth (Parapoynx diminutalis) from Asia probably entered the US via the aquarium trade. It was discovered feeding on hydrilla in Florida in 1976. The life cycle ofParapoynx is completed in 4-5 weeks. The moth was never approved for release, but large populations of hydrilla are occasionally completely defoliated by the larvae. It was later found that the moth is not a hydrilla specialist.

 

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Chinese grass carp (Ctenopharyngodon idella), a fish from China, is one of the most effective biological control agents for hydrilla and a number of other aquatic plants. The voracious herbivore prefers hydrilla and 2-25 fish can completely control one acre of the plant. Unfortunately, the fish does not eat only hydrilla and also will consume most submersed and emersedaquatic plants once hydrilla is depleted. Florida's interconnected surface waterways make it nearly impossible to restrict the range of grass carp. Because of the potential environmental damage caused by a breeding population of grass carp, a sterile "triploid" grass carp can be produced by treating fertilized eggs with cold, heat or pressure. It is legal in Florida to use grass carp forbiological control with a permit from the Florida Fish and Wildlife Conservation Commission (FWC). An efficient means of recapturing grass carp has not yet been developed and this limits the feasibility of employing the fish as a biological control agent. Triploid grass carp are stocked at very low rates (1-2 fish/acre) to control hydrilla in about 80 small Florida public waters (less than 500 acres in size and relatively self-contained).

For more detailed information about the use of grass carp, go to this page of the website or viewthis Extension publication and visit the Hydrilla IPM Project page for information about recent research on hydrilla management.

 

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Water hyacinth (Eichhornia crassipes)


Three biological control insects have been imported, studied, and released to control invasive water hyacinth, a floating macrophyte that was introduced to the U.S. during in the late 1800s. Together, these insects reduce the size and vigor of water hyacinth, and reduce flower and seed production. Individually, however, they are not able to control water hyacinth.


 

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The mottled water hyacinth weevil (Neochetina eichhorniae) was first released in 1972. The adults feed on the leaves and petioles of water hyacinth, where they produce characteristic feeding scars. The larvae tunnel in the petioles and crown of the plant. The mottled water hyacinth weevil has been the most effective biological control insect for water hyacinth. It is able to stress plants, reduce flowers and seeds, and reduce plant vigor.

 

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The chevroned water hyacinth weevil (Neochetina bruchi) is very similar to N. eichhorniae. It was first released in 1974. Both weevils reduce plant vigor and seed production and are damaging to young water hyacinth stands. Studies have shown a substantial decrease in plant growth when the insect is used in conjunction with herbicides. The weevils are unable to effectively control plants growing in water bodies with high nutrient loads (e.g., at wastewater treatment facilities); the plants simply outgrow the effects of herbivory.

 

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The water hyacinth moth (Niphograpta (=Sameodes) albiguttalis) was first released in 1977. The larvae feed by tunneling into the petioles of the younger, bulbous form of water hyacinth. The moth has been less successful as a biological control agent because it disperses rapidly, has patchy distribution, and may be completely excluded by the weevils on the older, non-bulbous plants.

 

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The water hyacinth planthopper (Megamalus scutellaris) was released in Florida in 2010. Both the nymphs and adults feed on the sap of water hyacinth, and the females deposit eggs into the leaf tissue. The insect's population increases rapidly, which will enable it to quickly impact water hyacinth. Nymphs are active and readily hop off the plant if disturbed. Because of its mobility, this insect may integrate better with existing maintenance control programs utilizing herbicides.

 

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Water hyacinth mite (Orthogalumna terebrantis) is an arachnid native to the U.S. In high numbers, these mites can desiccate water hyacinth foliage and cause leaves to turn brown. Severe damage may occur in small areas, but rarely does this mite attain high enough populations to provide area wide control of water hyacinth.

 

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Water lettuce (Pistia stratiotes)

Two South American insects have been released in Florida to combat water lettuce. Only one of these insects is established, but it has not adequately controlled or stressed the plant populations in most situations
The water lettuce leaf weevil (Neohydronomus affinis) was imported from South America after showing promising results as a biological control agent in Australia and South Africa. It was imported to the U.S. in 1986 and 1988. Two years after its release, the weevil population increased and effectively suppressed water lettuce at several sites. It is now established and distributed widely throughout the state, but rarely suppresses water lettuce growth. Adults and larvae feed on the leaves, crown and newly emerging shoots, and the characteristic holes in leaves indicates high weevil densities. Feeding by multiple larvae destroys the spongy leaf bases, which causes plants to lose buoyancy. The life cycle of the weevil is completed in 3 to 4 weeks. The weevil has not contributed to long-term suppression of the plant in the US, but has provided successful biological control of water lettuce in other countries. It is thought that the weevil is heavily preyed upon by imported fire ants in Florida. If true, this provides an interesting example of an exotic insect controlling a valuable potential biological control agent.

 

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The water lettuce leaf moth (Spodoptera pectinicornis) is native to Southeast Asia and was imported from Thailand. The caterpillar was first released in Florida in 1990, but failed to establish. Fire ant predation also may have prevented establishment of the moth. In its native range, augmentive releases of the moth have been successfully used to control water lettuce in rice paddies.​
 

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Melaleuca (Melaleuca quinquenervia)
Four insects have been released in Florida to combat melaleuca, an invasive weedy tree intentionally imported from Australia in 1906. Two of these biological control insects are well-established and significantly impacting melaleuca. The third insect failed to establish but the fourth is now well-established.

 

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The melaleuca leaf weevil (Oxyops vitiosa) was imported from Australia in 1992, and released in 1997 to slow the spread of melaleuca. The insect feeds on the young leaves, stems, and buds of the trees and interferes with normal plant processes such as seed production and plant growth. A new weevil generation is produced in approximately 3 months. This biological control agent is now widely established except in flooded areas, where the insect is prevented from completing its development in the soil.


 

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The melaleuca psyllid (Boreioglycaspis melaleucae) was released in 2002. Itspread very quickly due to wind dispersal and a short generation time of 1.5 months. Damage to melaleuca is caused primarily by the nymphs, which attack older leaves and woody stems as well as new leaves and seedlings. Unlike the weevil, the psyllid is able to complete its development entirely in the tree canopy under flooded conditions that effectively exclude the weevil.

 

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The melaleuca bud-gall fly (Fergusonina turneri) was first released in Florida in 2005. This insect is associated with a parasitic nematode. The female fly deposits her eggs, along with juvenile nematodes, into developing melaleuca buds. The nematodes induce gall formation and the fly larvae feed on the gall tissue. A new generation is produced in about 2 months. To date, this insect has failed to establish, even after multiple releases.

 

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The melaleuca stem-gall midge (Lophodiplosis trifida) was released in 2008, and establishment of this insect has been confirmed. Adults are tiny, fragile flies with long legs and antennae. They do not feed and are short-lived. Females are recognized by the red-orange eggs visible through the abdomen. Eggs are deposited singly or in groups on young stems, buds, and leaves of melaleuca. Larval feeding induces gall formation, primarily on the stems. Gall formation impedes stem growth, and small plants that are attacked often are killed.

 

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Common and giant salvinia (Salvinia spp.)

A tiny black weevil, Cyrtobagous salviniae, is the only insect that has been released as a biological control agent of giant salvinia (Salvinia molesta). Adventive weevils of one biotype that were discovered in Florida in 1960 are used to control common salvinia (Salvinia minima), whereas weevils of another biotype released in 2001 from a Brazilian population are used as biological control agents for giant salvinia.

Adult salvinia weevils (Cyrtobagous salviniae) feed on leaf buds and leaves. Larvae tunnel inside the plant, killing leaves and rhizomes. The entire life cycle of the Cyrtobagous weevil takes approximately 46 days. Attacked plants turn brown and eventually lose buoyancy. Cyrtobagous weevils from Australia are currently of great interest to researchers and have been introduced as a biological control agent for giant salvinia in the U.S. The effectiveness of these weevils for controlling salvinia in the US was recently confirmed in Texas and Louisiana.
Other biological controls studied in the past include: Some snails feed on several species of aquatic plants but have not proven effective as biological control agents.
Research, implementation, and results of biological controls are slow. Therefore, it is important to explore other control methods such as chemical, mechanical and physical, while establishing newbiological control agents. Protocols for integrating biological control agents with other control practices must also be developed.


 

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Classical Biological Control of Brazilian Peppertree (Schinus terebinthifolius) in Florida[SUP]1[/SUP]

J.P. Cuda, J.C. Medal, D.H. Habeck, J.H. Pedrosa-Macedo and M. Vitorino [SUP]2[/SUP]

Brazilian peppertree, Schinus terebinthifolius Raddi (Anacardiaceae), also known as Christmasberry, Florida Holly, and aroeira (Brazil), is an aggressive, rapidly colonizing invasive weed of disturbed habitats, natural communities and conservation areas in peninsular Florida (Cuda et al. 2004, 2006). Native to Argentina, Paraguay and Brazil, Brazilian peppertree was introduced into Florida as a landscape ornamental in the late 19th century (http://edis.ifas.ufl.edu/FW037 ). The popularity of Brazilian peppertree as an ornamental plant can be attributed to the numerous bright red drupes (fruits) produced during the October to December holiday season (Figure 1). Grown as a substitute for the more traditional English holly (Ilex aquifolium L.), Brazilian peppertree was common in cultivation in Florida during the first half of the 20[SUP]th[/SUP] century. However, this relative of poison ivy was a rare component of the native flora in Florida until the late 1950s when the first naturalized plants were discovered in Monroe County.
Figure 1. Leaves and fruit of Brazilian peppertree.

Credits: A. Murray, University of Florida, Center for Aquatic and Invasive Plants (used with permission).
Brazilian peppertree currently dominates entire ecosystems in southcentral Florida (Cuda et al. 2006). It is considered an important invader of theEverglades National Park, and poses a significant threat to ongoing Everglades restoration efforts. Once established, Brazilian peppertree quickly displaces the native vegetation, often forming dense monocultures that reduce the biological diversity of plants and animals in the invaded area. Although herbicides (http://edis.ifas.ufl.edu/AA219 ) and mechanical or physical control practices (e.g., cutting, burning and flooding) are routinely used often in combination for controlling existing stands (http://ipm.ifas.ufl.edu/pdf/BPmanagPlan.pdf), these conventional methods are expensive, labor intensive and provide only temporary control due to the plants regenerative capacity. Furthermore, non-selective chemical and mechanical controls are unsuitable for sensitive natural areas (e.g., coastal mangrove forests) because they can have negative effects on non-target species and increase water pollution. Minimizing the use of herbicides and other non-selective control practices is needed to maintain the integrity of Florida's fragile environment and natural resources. Biological control- the introduction of host-specific natural enemies into Florida that are capable of selectively damaging Brazilian peppertree- will accomplish this goal.
In the 1980s, Brazilian peppertree was identified as a suitable target for introductory or classical biological control (Habeck et al. 1994). Biological control is an appropriate management tactic because the invasive characteristics exhibited by Brazilian peppertree are consistent with the enemy release hypothesis (Williams 1954). The key elements of this hypothesis are that (a) native host specific enemies strongly control the abundance and distribution of native plants; (b) escape from host specific enemies is a key contributor to exotic plant success; and (c) enemy escape benefits exotic plants because they gain a competitive advantage over native plants as a result of being liberated from their herbivores. Also, because no close relatives of Brazilian peppertree occur in the US, the potential for non-target damage by approved biological control agents would be low.
Several insects have been identified from exploratory surveys conducted in Argentina, Brazil, and Paraguay as potential biological control agents of Brazilian peppertree (Habeck et al. 1994, Hight et al. 2002, Cuda et al. 2006, McKay et al. 2009). The following insects were selected for further study because they visibly damage the plant in its native range and were collected only from Brazilian peppertree or a few closely related species during field surveys.
Brazilian Peppertree Thrips, Pseudophilothrips ichini

The biology and field host range of Pseudophilothrips ichini (Hood) (Thysanoptera: Phlaeothripidae) were studied in southeastern Brazil (Garcia 1977). Pseudophilothrips ichini has not been observed feeding on plants other than Brazilian peppertree in it native range (Garcia 1977, J. H. Pedrosa, pers. observ.). Because this thrips was found attacking only Brazilian peppertree in field surveys, Garcia (1977) suggested that P. ichini might be a good candidate for biological control of this invasive weed. Recently, P. ichini was found to be a complex of two cryptic species (Cuda et al 2009, Mound et al 2010).
The life cycle of P. ichini begins when the female deposits her eggs on the leaves of the plant. After hatching, the immature thrips undergo two larval instars that are the active feeding stages. The wingless larvae are red or orange in color (Figure 2). As soon as the larval feeding phase is completed on the host plant, the remainder of the life cycle occurs in or on the soil. Unlike other families of the Thysanoptera that have only two pupal instars (the propupa and pupa), thrips belonging to the family Phlaeothripidae that includes P. ichini are unique in that they undergo three non-feeding pupal instars (the propupa, pupa I and pupa II) instead of two (Mound and Marullo 1996). Although these developmental phases are not true larvae or pupae, these terms are commonly used to describe the immature stages in a thrips life cycle.
Figure 2. Pseudophilothrips ichini, a thrips that kills the shoot tips of Brazilian peppertree. Adult female (left); larvae on young stem (right).

Credits: (adult) M. Vitorino, University of Blumenau; (larvae) D. H. Habeck, University of Florida.
Adults of P. ichini are black, winged, and relatively small (3-6 mm) (Figure 2), but have a high reproductive rate. Pseudophilothrips ichini is polyvoltine; up to four generations per year have been observed in Curitiba, Brazil, and it is considered a common species in its native range (Garcia 1977). Mating is not required to produce offspring. Unmated females deposit eggs that develop only into males whereas mated females produce eggs that develop into females (Mound and Marullo 1996). This form of parthenogenetic reproduction is called arrhenotoky.
In Brazil, the adults overwinter on Brazilian peppertree. In early spring (September), females start laying eggs singly or in small groups on the leaflet pedicels and blades, or on the new tender shoot growth. The duration of the immature stages is variable, depending on climate and other factors. The larvae hatch from the eggs in 7-8 days at 24 [SUP]o[/SUP]C. The first and second instars last 6 days and 11-12 days, respectively. The two-nonfeeding prepupal and pupal stages require ~ 8 days to complete their development. After transformation to the adult stage, females undergo a 5 to 15 day preoviposition period, and can oviposit up to 220 eggs during their lifetime (45-78 days). Duration of the complete life cycle for P. ichini is temperature dependent. According to Garcia (1977), the life cycle from egg to egg was completed in 76 days at 18 [SUP]o[/SUP]C, and 38 days at 24 [SUP]o[/SUP]C. Under laboratory conditions, females lived on average 78 days at 23.1 [SUP]o[/SUP]C when maintained in vials provided with food.
Both the larval and adult stages damage the plant. Larvae of P. ichini usually are found clustered around the stem of a tender shoot (Fig. 2). They feed by rasping and sucking the plant sap, which frequently kills the growing tip. Adults are usually found on the new unfolding leaves where they feed, mate, and oviposit. Although they can be more randomly distributed on the plant, adults usually are found aggregated with the developing larvae. Adults also will feed on the flowers, causing them to abort. This type of feeding damage can inhibit seed production in mature plants and has beeen shown to reduce the growth rate of younger plants (Furmann et al. 2005). In addition, there is anecdotal evidence suggesting that feeding damage by P. ichini promotes infection by plant pathogens that contributes to shoot death (R. Barreto, pers. comm.).
The laboratory host range of P. ichini was investigated in an approved Florida containment laboratory (Cuda et al. 2009). A petition to release P. ichini from quarantine was initially prepared and submitted to the federal interagency Technical Advisory Group for the Introduction of Biological Weed Control Agents, or TAG (http://edis.ifas.ufl.edu/ENY828 ) in November 1996. Request for release from quarantine was initially denied because the biological and host range testing data presented in the original petition did not adequately address the risk to native Caribbean plant species and to the closely related California peppertree, Schinus molle L., a common introduced ornamental in southern California. A new petition to release the thrips in Florida was prepared and resubmitted to the TAG in October 2002 (Cuda et al. 2002). The revised petition adequately addressed all of the concerns raised by reviewers in the earlier petition, and the TAG recommended field release of P. ichini in May 2007.
Brazilian Peppertree Sawfly, Heteroperreyia hubrichi

Heteroperreyia hubrichi Malaise (Hymenoptera: Pergidae) is a primitive non-stinging wasp native to northern Argentina and southeastern Brazil. The biology, ecology and host range of the sawfly H. hubrichi were investigated in Brazil, Florida, and Hawaii (Vitorino et al. 2000, Medal et al. 1999, Hight et al. 2002, Cuda et al. 2005). The larval stage of this insect is phytophagous (plant feeding). The adults are black with yellow legs (Figure 3), and the ***es can be separated on the basis of size (females are larger), the presence of the ovipositor in females, and also antennal morphology. Field data collected in Brazil indicate this species is bivoltine (2 generations per year). *** ratio of the adults is approximately 1:1 (males to females) when reproduction is bi***ual, but the sawfly also exhibits arrhenotoky; mated females produce females and unmated females produce only males. In Brazil, a pupal diapause period occurs in the summer (December to February) and winter (June to August).
Figure 3. Heteroperreyia hubrichi, a defoliating sawfly of Brazilian peppertree. Adult female guarding egg mass inserted into stem (left); gregarious larvae feeding on leaflet (right).

Credits: J. C. Medal, University of Florida.
Upon emergence from the pupal stage, females mate and/or oviposit in young woody branches that are adjacent to the more tender terminal shoots. This behavior enables the sawfly to avoid the toxic resin common in the Brazilian peppertrees terminal growth. The female uses her saw-like ovipositor to cut the stem tissue and insert her eggs between the thin bark and the phloem (Figure 3). The eggs are elliptical in shape, and are deposited side by side in long rows of variable length and number. Females exhibit maternal behavior by guarding the egg masses during the incubation period, but die as soon as the first larvae hatch.
The period of egg maturation is about 15 days. The number of eggs is directly linked to the size of egg mass. The average number of eggs per mass is ~ 100. Females prefer to oviposit on plants that are < 3 m in height, and select young branches with a diameter between 2.5 to 5 mm for oviposition. In Brazil, the majority of sawfly egg masses (76.5%) occurred on plants with hairy leaves (varietiespohlianus and rhoifolius). However, in laboratory and greenhouse studies, sawflies readily accepted var. raddianus, the smooth variety of Brazilian peppertree that commonly occurs in Florida.
The larvae are bright green with a black head capsule (Figure 3), and have red areas at the end of abdomen and adjacent to the head capsule in the last two instars. The larval stage has seven instars in the females and six in the males. The duration of the larval stage (from emergence of the neonate larvae to pupation) is 45 days. The pre-pupal phase is characterized by the change in the size of the last instar larvae (25% smaller), and cessation of feeding. In this phase, the larvae burrow in the soil to a depth ranging from 3 to 4 cm to pupate. The pupation chamber acquires the color of the surrounding soil, and is ~ 1 cm in length, and ~ 0.5 cm in width. The pupal stage lasts from 1 to 5 months, with an average of 4 months.
The larva of H. hubrichi is the damaging stage. Developing larvae are voracious leaf feeders (Figure 3), and can cause complete defoliation of Brazilian peppertrees depending on the size of the plant and quantity of larvae present. This type of feeding damage could severely injure or kill young plants and prevent older plants from reproducing, which would reduce the competitive advantage that Brazilian peppertree currently holds over native vegetation. In Brazil, it is not uncommon to find Brazilian peppertree shrubs and more rarely trees completely defoliated by the sawfly. Larvae are gregarious in the early instars, and feed in groups on tender leaves mainly on new shoots. When the larvae reach the third instar, they disperse over the plant and attack leaves of all age classes.
Since the entire life cycle from adult to adult can be completed in less than 4 months under ideal conditions, this insect may be capable of producing two or three generations per year in central and south Florida where Brazilian peppertree is a severe problem. Simulated herbivory studies conducted under field conditions in south Florida over a 2-year period have shown that growth and reproduction of Brazilian peppertrees are severely impacted when the plants are subjected to multiple defoliations within the same growing season (Treadwell and Cuda 2007).
The TAG recommended field release of the defoliating sawfly H. hubrichi in Florida in 1997. However, a release permit was not issued by APHIS PPQ because of concerns raised about toxins present in the larvae, which could have a negative impact on native fauna if the larvae were ingested.
Brazilian Peppertree Leaflet Roller, Episimus unguiculus

Episimus unguiculus Clarke, previously known as E. utilis Zimmerman (Lepidoptera: Tortricidae), was introduced into Hawaii for classical biological control of Brazilian peppertree in the 1950s (Krauss 1963). Martin et al. (2004) investigated the biology of E. unguiculus in the process of establishing a laboratory colony for conducting host range tests in an approved Florida containment laboratory. Adults (Figure 4) are small, grayish brown moths with distinctive markings on the forewings. When at rest, the adults are cryptically colored, resembling either tree bark or bird droppings. ***es can be readily separated without magnification by examining the wing pattern. Average life span for the adult moths is 8 to 9 days, and development from egg to adult stage occurs in about 42 days.
Figure 4. Adult (top) and mature larva (bottom) of Episimus unquiculus, a leafrolling moth introduced into Hawaii for biological control of Brazilian peppertree.

Credits: Photo of larva by M. Fukada, Hawaii Department of Agriculture. (Used with permission).
Females can deposit up to 172 eggs during their lives. Eggs are usually deposited singly but occasionally in groups of up to six eggs on the upper and lower surfaces of Brazilian peppertree leaflets. The eggs, which are glued to the leaflet, are compressed, ovoid, and light green in color with a smooth chorion when first deposited but darken as they develop. The thin, scale like shape and transparency of freshly deposited eggs probably afford them some protection from predation and possibly parasitism.
The caterpillar (or larval stage) of E. unguiculus (Figure 4) attacks the foliage of Brazilian peppertree. Early instars are tan to light green in color but as they reach maturity, the larvae turn bright red before pupating and are approximately 15 mm long. The larval stage has 5 instars although a 6[SUP]th[/SUP] instar may occur on occasion.
Feeding habits of the larvae vary depending upon their age. Newly hatched larvae and early instars feed by scraping the surface of the leaflets. Early instars are leaflet tiers, and normally feed between young and expanding leaflets that have been tied together with silk. The 1[SUP]st[/SUP] to 3[SUP]rd[/SUP] instars typically web together two or more adjacent leaflets flat against each other. Older larvae bind single leaflets into the characteristic cylindrical roll that is usually associated with E. unguiculus in nature. A cohort of approximately 35 larvae is capable of completely defoliating a 0.5 m tall Brazilian peppertree potted plant in less than 3 weeks (Martin et al. 2004). The results of a recent study by Manrique et al. (2009) showed that high levels of defoliation by E. unguiculus significantly reduced the number of leaflets, plant height, foliar biomass, relative growth rate (RGR) and shoot: root ratio of potted Brazilian peppertrees. Moreover, plants were not able to recover from the effects of the herbivory after 2 months.
Unlike the sawfly H. hubrichi that pupates in the soil and is vulnerable to flooding and possibly ant predation, mature larvae of E. unguiculus pupate in the tree canopy inside rolled leaflets attached to the plant. Pupae are brown in color with the head, appendages and wings darker than the abdomen.
In Hawaii, where it was released in the 1950s, E. unguiculus is widely distributed on Brazilian peppertree, but the insect apparently is not sufficiently abundant to severely damage the plant (Yoshioka and Markin 1991, J.P. Cuda 2002, personal observation). The ineffectiveness of E. unguiculus as a biological control agent in the Hawaiian Islands may be due in part to biotic mortality factors unique to that environment. For example, two wasps that were introduced into Hawaii for classical biological control of the sugar cane leafrollerHedylepta (=Omiodes) accepta (Butler) were discovered attacking E. unguiculus soon after it was released against Brazilian peppertree (Krauss 1963).
Although satisfactory biological control of Brazilian peppertree by E. unguiculus was not achieved in the Hawaiian archipelago, this failure should not preclude the introduction of the insect into Florida. Episimus unguiculus could be a more effective biological control agent of Brazilian peppertree in Florida because it would be introduced into a new environment where biotic mortality from introduced and native parasitoids and predators may be less severe in Florida compared to Hawaii. Host range testing has been completed and a release petition was submitted to the TAG in Setember 2009.
Brazilian Peppertree Stem Boring Weevil, Apocnemidophorus pipitzi

Surveys conducted recently in northern Argentina (McKay et al., 2009), and southeastern Paraguay revealed the presence of several new natural enemies of Brazilian peppertree. Among these were two species of stem boring weevils belonging to the genusApocnemidophorus Hustache. The weevils resemble bird droppings.and immediately drop off the plants when they are disturbed. Adults of Apocnemidophorus pipitzi (Faust) were collected in southeastern Paraguay and imported into a Florida containment laboratory in April 2006. According to Wibmer and O'Brien (1986), A. pipitzi is native to Argentina, Brazil and Uruguay. An examination of weevil specimens deposited in the entomology museum of the Federal University of Parana in Curitiba, Brazil, revealed that collections of A. pipitzi have been made in the states of Parana, Santa Catarina, and Minas Gerais. The occurrence of A. pipitzi in Paraguay is a new country record for this species
The adults range in size from 4 to 7 mm in length and are grayish brown in color, with live specimens often appearing more creamy than grayish (Figure 5). A thick patch of white scales is clearly visible on the sides of the pronotum and is less pronounced on the underside of the abdomen. Other parts of the body have just a few scattered areas with white scales. There also are several patches of black scales over the elytra which are generally clearly visible under magnification, giving the elytra (forewings) a slightly mottled appearance.
Figure 5. Egg, larva, pupa and adult male of the weevil Apocnemidophorus piptzi. The larvae mine the stems and the adults feed on the leaflets of Brazilian peppertree.

Credits: Lyle Buss, University of Florida.
The ***es of A. pipitzi are readily distinguishable. According to C. W. O'Brien (person. comm.), there are obvious differences in the rostrum (snout) and antennal insertion in males and females of A. pipitzi. The females have an evenly curved relatively uniformly cylindrical rostrum with no difference in diameter or curvature at the antennal insertion. In contrast, the males have a strong dorsal expansion at the antennal insertion and the rostrum is narrowed beyond the insertion and strongly angled ventrally and dorsally flattened. This is evident even in very small specimens. Other species of the genus, some very similar in appearance, do not have such obvious male differences in the rostrum.
The life stages of A. pipitzi are shown in Figure 5. The adults are long–lived, surviving in the laboratory for almost 2 months. Females chew small holes (ca. 0.5 mm) into the stems and then insert their ovipositors into the cavities. After depositing an egg (or multiple eggs), they seal the cavities with a frass plug that initially is bright green in color but eventually turns brown. The entire process lasts approximately 45 minutes. In the laboratory, a new generation of weevils emerged from cut stems of Brazilian peppertree in 3 to 4 months. The length of the life cycle suggests that multiple generations of A. pipitzi would be produced annually if this insect were approved for release in Florida.
Both the adults and larvae of A. pipitzi are capable of damaging Brazilian peppertree. Adults feed preferentially on the tender, subterminal leaflets of the plant. The characteristic feeding scars produced by the adults generally do not completely perforate the leaflets, causing a thin, translucent layer of plant tissue or “window” to remain. However, leaflets that sustain heavy feeding damage eventually abscise. The larvae (Figure 5) tunnel extensively just under the bark of BP (in the vicinity of the cambium) until they reach the pupal stage. This type of feeding damage can weaken the plant because it interferes with the normal transport of water and nutrients in the xylem and phloem tissues.
References

Cuda J.P., A.P. Ferriter, V. Manrique, and J.C. Medal (eds.). 2006. Florida's Brazilian peppertree management plan, 2nd edition: Recommendations from the Brazilian peppertree Task Force, Florida Exotic Pest Plant Council, April 2006. Available athttp://ipm.ifas.ufl.edu/pdf/BPmanagPlan.pdf.
Cuda, J.P., D.H. Habeck, S.D. Hight, J.C. Medal, and J.H. Pedrosa-Macedo. 2004. Brazilian Peppertree, Schinus terebinthfolius: Sumac Family-Anacardiaceae, pp. 439-441. In E. Coombs, J. Clark, G. Piper, and A. Cofrancesco (eds.), Biological Control of Invasive Plants in the United States. Oregon State University Press, Corvallis, OR.
Cuda, J.P., J.C. Medal, J.H. Pedrosa-Macedo, and D.H. Habeck. 2002. Request for field release of a nonindigenous thripsPseudophilothrips ichini (Thysanoptera: Phlaeothripidae) for classical biological control of Brazilian peppertree, Schinus terebinthifolius(Anacardiaceae), in Florida (Submitted to IFAS and TAG October 2002). 53 pp.
Cuda, J.P., J.C. Medal, J.L. Gillmore, D.H. Habeck, and J.H. Pedrosa-Macedo. 2009. Fundamental host range of Pseudophilothrips ichiisensu lato (Thysanoptera: Phlaeothripidae), a Anacardiaceae) in the USA. Environ. Entomol. 38: 1642-1652.
Cuda, J.P., J.C. Medal, M.D. Vitorino, and D.H. Habeck. 2005. Supplementary host specificity testing of the sawfly Heteroperreyia hubrichi,a candidate for classical biological control of Brazilian peppertree, Schinus terebinthifolius, in the USA. BioControl 50: 195-201.
Furmann, L.E., J.H. Pedrosa-Macedo, J.P. Cuda, and M.D. Vitorino. 2005. Efeito da liberação no campo de Pseudophilothiprs ichini no desenvolvimento de Schinus terebinthifolius. Floresta 35: 241-245.
Garcia, C.A. 1977. Biologia e aspectos da ecologia e do comportamento defensiva comparada de Liothrips ichini Hood 1949 (Thysanoptera Tubulifera). M.S. Thesis, Universidade Federal do Parana, Curitiba, Parana, Brazil.. 75 p.
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Hight, S.D., J.P. Cuda, and J.C. Medal. 2002. Brazilian peppertree. Pages 311-321 in R. Van Driesche, B. Blossey, M. Hoddle, S. Lyon, and R. Reardon (eds.). Biological Control of Invasive Plants in the Eastern United States. US Forest Service, Morgantown, WV, FHTET-2002-04.
Krauss, N.L.H. 1963. Biological control investigations on Christmas berry (Schinus terebinthifolius) and emex (Emex spp.). Proc. Hawaiian Entomol. Soc. 18: 281-288.
Manrique, V. J. P. Cuda, and W. A. Overholt. 2009. Effect of herbivory on growth and biomass allocation of the invasive Brazilian peppertree (Sapindales: Anacardiacea) seedlings in the laboratory. BioControl Sci. & Tech. 19: 657-667.
Martin, C.G., J.P. Cuda, K.D. Awadzi, J.C. Medal, D.H. Habeck and J.H. Pedrosa-Macedo. 2004. Biology and laboratory rearing of Episimus utilis (Lepidoptera: Tortricidae), a candidate for classical biological control of Brazilian peppertree, Schinus terebinthifolius(Anacardiaceae), in Florida. Environ. Entomol. 33 1351-1361.
McKay, F., M. Oleiro, G.C. Walsh, D. Gandolfo, G.S. Wheeler, and J.P. Cuda. 2009. Natural enemies of Brazilian peppertree (Schinus terebinthifolius: Anacardiaceae) from Argentina: their possible use for biological control in the USA. Florida Entomol. 92: 292-303.
Medal, J.C., M.D. Vitorino, D.H. Habeck, J.L. Gillmore, J.H. Pedrosa, and L.D. De Sousa. 1999. Host specificity of Heteroperreyia hubrichiMalaise (Hymenoptera: Pergidae), a potential biological control agent of Brazilian Peppertree (Schinus terebinthifolius Raddi). Biological Control 14: 60-65.
Mound, L.A., and R. Marullo. 1996. The thrips of Central and South America: an introduction (Insecta: Thysanoptera). Memoirs Entomol. International 6: 1-487.
Mound, L.A., G.S. Wheeler, and D.A. Williams. 2010. Resolving cryptic species with morphology and DNA; thrips as a potential biocontrol agent of Brazilian peppertree, with a new species and overview of Pseudophilothrips (Thysanoptera). Zootaxa 2432: 59-68.
Treadwell, L.W. and J.P. Cuda., J.P. 2007. Effects of defoliation on growth and reproduction of Brazilian peppertree (Schinus terebinthifolius). Weed Science 55: 137-142.
Vitorino, M.D., J.H. Pedrosa-Macedo, and J.P. Cuda. 2000. Biology and specificity tests of the sawfly – Heteroperreyia hubrichi Malaise, 1955 (Hymenoptera: Pergidae) a potential biological control agent for Brazilian peppertree- Schinus terebinthifolius Raddi (Anacardiaceae). In: N.R. Spencer (ed.), Proceedings of the X International Symposium on Biological Control of Weeds, 4-14 July 1999, Montana State University, Bozeman, Montana, USA. USDA, ARS, Sidney, Montana and Montana State University, Bozeman, Montana. pp. 645-650.
Wibmer, G.J. and C.S. OBrien. 1986. Annotated checklist of the weevils (Curculionidae sensu lato) of South America (Coleoptera: Curculionoidea). Mem. Amer. Entomol. Institute 39. American Entomological Institute, Gainesville, FL.
Williams, J. R. 1954. The biological control of weeds. - In: Report of the Sixth Commonwealth Entomological Congress, London, UK, pp. 95-98.
Yoshioka, E.R., and G.P. Markin. 1991. Efforts of biological control of Christmas berry Schinus terebinthifolius in Hawaii. pp. 377-385. In T. Center et al. (eds.), Proceedings of the symposium of exotic pest plants, 2-4 November 1988. Miami, FL.
Footnotes

1.
This document is ENY-820 (IN114), one of a series of the Entomology and Nematology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date: September 1999. Revised: July 2010. Please visit the EDIS Website at http://edis.ifas.ufl.edu.
2.
J.P. Cuda, J.C. Medal, D.H. Habeck, Entomology and Nematology Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611; J.H. Pedrosa-Macedo, Federal University of Parana, Laboratory of Forest Protection, Curitiba, Brazil and M. Vitorino, University of Blumenau, Blumenau, Brazil.​
 

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