Location: Biological Control of Pests Research
2016 Annual Report
Objectives
Objective 1: Discover new biological control agents for invasive insect pests, especially invasive hemipterans, such as the bagrada bug and the kudzu bug.
Objective 2: Develop practical, mass rearing methods for agriculturally important insects, especially insect pests needed for the production of their natural enemies (such as stink bugs), insect biological control agents (such as predatory pentatomids and coccinellids), and insects potentially important as a food supply for animals and humans (such as mealworms and crickets).
Sub-objective 2A: Develop a reliable method for continuous production of the green stink bug Nezara viridula.
Sub-objective 2B: Study new methods to produce extracts from the yellow mealworm Tenebrio molitor and the house cricket Acheta domesticus and incorporate them into artificial diets for the predators Podisus maculiventris and Coleomegilla maculata.
Sub-objective 2C: Evaluate agricultural by-products as sources of food for the production of Tenebrio molitor and Acheta domesticus.
Objective 3: Develop effective biological control strategies for insect pests of crops grown under cover (e.g. high tunnels and greenhouses).
Approach
Climate matching software will be used to determine the most likely locations of natural enemy adapted populations across native ranges of M. cribraria and B. hilaris. The USDA-ARS European Biological Control Laboratory near Montpellier, France, will play a key role regarding parasitoid introductions of B. hilaris from many regions of Asia and Africa. Scientists at the university in Japan will make additional collections across the geographic range of the host within Japan. Scientists at USDA-ARS-IIRU, Newark, DE, will provide his host specificity expertise and make his Asian contacts available for the Kudzu Bug project.
Development of artificial diets for N. viridula will be approached by detailed chemical analyses of plant foods suitable for development and reproduction of N. viridula approximating their nutritional requirements. Artificial diets will be formulated to replicate the concentration and ratios of major nutritional components of broccoli, green lima beans and raw peanuts, which have been used to rear N. viridula. Diets will be compared to natural food sources broccoli, green snow peas, and raw peanuts plus a nutrient supplement previously developed (unpublished). Rearing conditions other than diet, such as optimal rearing density and adult reproductive curves, will also be studied.
Extracts of T. molitor larvae and pupae and A. domesticus nymphs will be produced by freeze-drying them at -25ºC and by spray drying of homogenized insects. Dry samples will be ground to particles of at least 30 µm. Extracts produced from dried T. molitor pupae will be used to produce artificial diet formulations for C. maculata. The diet formulations will be compared on their suitability to produce quality predators using life table analysis of C. maculata. The formulations will also be compared to a control consisting of natural food. The same procedure will be used for artificial diet formulations for P. maculiventris.
Four different types of agricultural by products will be tested as viable options to formulate diets for T. molitor and A. domesticus. 1) Peanut shells, 2) corn cobs, 3) discarded cabbage, and 4) residual from corn fermentation for ethanol production. Each by-product will be chemically analyzed to determine the content of protein, lipid, and carbohydrate. Diets will be formulated by mixing ingredients with wheat bran at different ratios depending of their nutrient content based on the chemical analyses. Diets will be evaluated by determining and comparing immature survival, development time and the efficiency of food conversion for each of the two species of insects.
Release and evaluation techniques for lady beetles as predators of strawberry will be develop and evaluated. This study will involve (A) testing the effectiveness of augmentative releases of lady beetles to control aphids in high tunnels, (B) testing the predation potential of larvae in the presence of aphid-tending ants in the laboratory and in high tunnels, and (C) testing the assertion that molecules in wax filaments on the cuticle of S. creperus larvae subdue ant aggression.
Progress Report
Two key natural enemies of the kudzu bug, Megacopta cribraria, were imported from Japan for host specificity testing against eggs of native stink bug species. The parasitoid wasp Ooencyrtus nezarae (Encyrtidae) could successfully attack most stink bugs tested, while Paratelenomus saccharalis (Platygastridae) was specific to kudzu bug eggs. Three species of egg parasitoids of the bagrada bug, Bagrada hilaris, were imported from Pakistan and colonized for host specificity testing.
New and improved rearing methods were developed for the pink spotted lady beetle (Coleomegila maculata) and two economically important stink bug species including the Southern green stink bug (Nezara viridula), and the Neotropical brown stink bug (Euschistus heros). The rearing systems of stink bugs were modified allowing the production of > 30,000 eggs, and more than 80,000 eggs per week for the Southern green and Neotropical stink bugs, respectively. Eggs were used by the cooperator companies to develop new pest control technologies against these two pests.
A colony of the house cricket (Acheta domesticus) has been established in the laboratory and maintained since August 2015. Multiple studies have been completed including, comparison of 2 commercial diets, age dependent food utilization at two temperatures (29 and 27°C), and evaluation of a new inverted water feeder. Self-selection studies are in progress, which will be the basis for new diet formulations using agricultural by-products. This information will be important to determine optimal times for harvesting crickets intended as food or animal feed. Protein, lipid and carbohydrate contents of five agricultural by products including peanut shells, distilled corn grains (DDG’s), defeated camelina seed, corn cobs, and brewer’s yeast were either compiled from literature sources when available, or determined by chemical analysis. This information will be used to develop insect diets using agricultural by-products.
Rearing colonies of one ant species, two lady beetle species, and two aphid species have been established in the laboratory. Strawberry (Camarosa and Chandler cultivars) plants have been potted in four, identical high tunnels, 24 feet long, and 18 feet wide, with screened side walls. Lady beetle releases onto strawberry plants are scheduled for summer and fall seasons. An exhaustive review of the literature on efficacy of lady beetle releases to control aphids on crop plants under cover (greenhouses and high tunnels) has been completed. Factors affecting success or failure of releases have been reviewed and discussed in a soon-to-be published manuscript.
Accomplishments
1. Developing improved mass rearing methods for the Neotropical brown stink bug (Euschistus heros). Current mass rearing system for the Neotropical brown stink bug have allowed the culture of this insect pest year round. However, current mass production strategies are inefficient and labor intensive. Plant resistance bioassays for development of new plant varieties require the production of more than 20,000 stink bug eggs per day. Researchers at the Biological Control of Pests Research Unit, Stoneville, Mississippi, have developed new cage designs, rearing methods, and a more efficient diet mix for the Neotropical brown stink bug. These advances have allowed a five-fold increase of egg production, surpassing production goals by improving immature survival, adult fecundity and egg viability. Trust agreements with industry have been fulfilled. The increase in Neotropical brown stink bug egg production has speeded research efforts on transgenic plant development by industry cooperators and allowed the establishment of similar efforts for different stink bug species.
2. Rearing of the pink spotted lady beetle (Coleomegilla maculata) for 7 generations exclusively on artificial diet. Previous research culminated in the development of an artificial diet formulation for the pink spotted lady beetle that was superior to the most common commercial food used to rear this beetle. However, this accomplishment would not have any value if the pink spotted lady beetle could not be reared in artificial diet for multiple generations. ARS scientists have maintained a colony of the pink spotted lady beetle since May, 2015 exclusively fed with artificial diet. Adult longevity, larval survival, and egg production remain normal and egg viability has not declined for 7 generations. This study will continue until 10 generations in artificial diet have been completed. The feasibility of maintaining this predator in artificial diet for multiple generations open the door for commercial application, The use of artificial diets for the production of predatory lady beetles can potentially reduce costs of production and benefit biological control producers as well as biological control users in the U.S.
3. Identifying oviposition stimulants for the pink spotted ladybeetle (Coleomegilla maculata) from plant-derived natural products. ARS researchers in Stoneville, Mississippi and Peoria, Illinois discovered that several bioflavonoids (plant secondary metabolites) stimulated oviposition in ladybird beetles. More precisely, powdered formulations of quercetin, taxifolin, naringenin, genistein, and catechin hydrate stimulated oviposition behavior in the pink spotted ladybeetle. For example, in 12-day bioassays involving multiple females (20 individuals/cage), oviposition was common in cages with quercetin, but rare in cages without quercetin. The stimulation of oviposition in the presence of bioflavonoids has the potential benefits of: (1) reducing cannibalism, by restricting egg-laying to a location away from feeding sites, and (2) increasing egg harvesting from a specific location rather than random locations in rearing cages. The possible end result will be more efficient mass production of ladybeetles for augmentative biological control of plant pests on small fruits and vegetables in commercial greenhouses and high tunnels.
None.
Review Publications
Mehmood, R., Jones, W.A., Bajwa, B.E., Rashid, K. 2015. Egg Parasitoids from Pakistan as possible classical biological control agents of the invasive pest, Bagrada hilaris (Heteroptera: Pentatomidae). Journal of Entomological Science. 50(2):147-149.
Morales Ramos, J.A., Rojas, M.G. 2015. Effect of larval density on food utilization efficiency of Tenebrio molitor (Coleoptera: Tenebrionidae). Journal of Economic Entomology. 108:2259-2267.
Morales Ramos, J.A., Rojas, M.G., Shelby, K., Coudron, T.A. 2015. Nutritional value of pupae versus larvae of Tenebrio molitor (Coleoptera: Tenebrionidae) as food for rearing Podisus maculiventris (Heteroptera: Pentatomidae). Journal of Economic Entomology. 109(2):564-571.
Riddick, E.W., Wu, Z. 2015. Effects of rearing density of survival, growth, and development of the ladybird Coleomegilla maculata in Culture. Insects. 6:858-868.
Riddick, E.W., Wu, Z. 2015. Does a change from whole to powdered food (Artemia franciscana eggs) increase oviposition in the ladybird Coleomegilla maculata. Insects. 6:815-826.
Rojas, M.G., Morales Ramos, J.A., Riddick, E.W. 2016. Use of Tenebrio molitor (Coleoptera: Tenebrionidae) powder to enhance artificial diet formulations for Coleomegilla maculata (Coleoptera: Coccinellidae). Biological Control. 100:70-78.
Cortez Ortiz, J.A., Torres Ruiz, A., Morales Ramos, J.A., Thomas, M., Rojas, M.G., Tomerlin, J.K. 2016. Insect mass production technologies. Insects as Sustainable Food Ingredients. 6:154-201.
