Foreign exploration for natural insect enemies that parasitizes Lygus lineolaris.
Tarnished plant bug and natural enemies natural host range.
General description of research:
Field exploration in South America led to the discovery of a beneficial parasitic wasp, called Leiophron argentinensis Shaw (Hymenoptera: Braconidae), that is new to science. This is important because this insect has the potential for controlling plant bugs in U.S. crops. In cooperation with the SABCL, field collections were made in Argentina and Paraguay. The eventual outcome could be the release of a beneficial insect in the U.S. Results from the preliminary trail indicated that L. argentinensis successfully parasitized L. lineolaris. Parasitism rates of first instars ranged from 2 to 20% for L. lineolaris. The fact that L. argentinensis accepted L. lineolaris and successfully developed on these hosts through two generations suggests that this parasitoid has potential for biological control of these pests in the United States. Although the entire geographic range of L. argentinensis is not currently known, this wasp clearly inhabits wide geographic and climatic ranges in Argentina and Paraguay (from at least 22-35° S latitude), suggesting that much of the United State would be suitable habitat for this parasitoid. Multivoltinism and the lack of obligate diapause also are attributes of L. argentinensis. Moreover, this wasp occurs on many of the same host plants that are infested by L. lineolaris, which would facilitate early-season suppression of bugs in spring weeds before dispersal into cotton. However, concerns about nontarget effects of introduced species (FAO 1997, Van Driesche and Hoddle 1997), especially in a "new-association" strategy, suggest further research before introduction of L. argentinensis is contemplated. Investigations of host-range evaluation and parasitoid competition will lead to a better understanding of the potential risks to nontarget mirids and native euphorines.
Foreign exploration to find parasitizing natural insect enemies in Argentina and Paraguay.
Chemical Ecology Studies Toward Biological Control of Tarnished Plant Bug
Plants respond to herbivory by producing volatiles that attract natural enemies of the herbivores responsible for the damage.
Does Lygus feeding and oviposition induce HIPVs? The blend of herbivore-induced plant volatiles (HIPVs) emitted after Lygus feeding is a complex mixture of compounds that vary in concentration. This blend is similar to that produced by plants fed on by caterpillars. Identification of elicitor in Lygus saliva
1.5 x 1.5 x 1.5 m cages 6 cotton plants arranged in a circle 3 plants with Lygus feeding and oviposition, 3 insect-free plants 200 Anaphes iole females released in center
Anaphes iole females were strongly attracted to cotton plants exposed to Lygus feeding and oviposition
Flight behavior study of TPB
Flight mills and vertical flight chamber results:
Most flights less than 5 minutes
Longer flights in bugs 1-3 weeks old
Bugs flew throughout the day and night, but most sustained flights by females were nocturnal
No correlation between flight parameters and egg load
Rate of climb was ca. 1 mph, indicating a capacity for strong, self-directed flights
The nutritional ecology of an important beneficial insect was studied. This is important because access to appropriate food sources increases the impact of beneficial insects. The effect of different food sources on the lifespan of the beneficial insect was determined. The work may lead to the development of strategies to provide beneficial insects with food sources that lead to maximum lifespan and impact on the pest insects.
Chemical ecology studies provided information that will facilitate selection of appropriate approaches for future field tests using synthetic or plant-derived compounds. Foreign exploration resulted in the collection of beneficial insects that have potential for controlling plant bugs in U.S. crops.
More visits to other countries in search of natural enemies of TPB's.
Further investigation of their flight behavior and extent of host range.
Future studies on the range of enemy hosts.
2005: Results from field exploration and subsequent host range trials should provide candidate species that are compatible for release.
2006: Evaluation of nutritional ecology investigations should provide information that will help determine the most appropriate approach to providing beneficial insects with food under field conditions in the Midsouth.
2007: Results of field trials with synthetic or plant-derived compounds will lead to appropriate strategies for using these compounds to manipulate behavior of beneficial insects and pests. These studies will be integrated into an Area-wide Insect Pest Management (IPM) system for suppression of heteropteran pests.
For more information contact:
Livy H. Williams
PO Box 346
141 Experiment Station Rd
Stoneville, MS 38776
Beach, J. P., L. Williams, III, D. L. Hendrix and L. D. Price. 2003. Different food sources affect the gustatory response of Anaphes iole, an egg parasitoid of Lygus spp. Journal of Chemical Ecology. 29: 1203-1222.
Williams, L., III, S. C. Castle and C. Rodriguez-Saona. Effect of herbivore-induced plant volatiles on Anaphes iole (Hymenoptera: Mymaridae) and Lygus spp.(Hemiptera: Miridae): electrophysiological and behavioral studies. Published abstracts of 13th International Entomophagous Insect Workshop, Tucson, AZ, July 2003. Journal of Insect Science. 3:33, p. 28. insectscience.org/3.33.
Williams, L., III, G. A. Logarzo, S. R. Shaw, L. D. Price and V. Manrique. 2003. Leiophron argentinensis Shaw (Hymenoptera: Braconidae) - a new species of parasitoid from Argentina and Paraguay, with information on life history and potential for controlling Lygus bugs (Hemiptera: Miridae). Annals of the Entomological Society of America 96: 834-846.
Williams, L., III, L. D. Price and V. Manrique. 2003. Toxicity of field-weathered insecticide residues to Anaphes iole (Hymenoptera: Mymaridae), an egg parasitoid of Lygus lineolaris (Heteroptera: Miridae), and implications for inundative biological control in cotton. Biological Control 26: 217-223.