Location: Biological Control of Pests Research2011 Annual Report
1a. Objectives (from AD-416)
The long-term objective of this project is to develop an improved understanding of the biology, nutrition, and behavior of natural enemies of pest arthropods. Our primary target pest will be the two-spotted spider mite, Tetranychus urticae. Some of the most important natural enemies of this mite are phytoseiid predatory mites and coccinellids. We aim to implement, improve and increase the mass rearing capabilities of these organisms by developing artificial diets and novel rearing technology to enable economical biological control of this pest by augmentation of its natural enemies and to develop novel techniques of quality control and quality assurance. Our work will focus on the following: (1) Determine nutritional, behavioral, and physical conditions necessary for in vivo and in vitro insect rearing and use the results to implement mass production systems of biological control agents. (2) Determine the impact of mass rearing procedures on survival, reproduction, and gene expression. (3) Assess optimal conditioning of insects for release.
1b. Approach (from AD-416)
Research activities will focus on a specific predator, Stethorus punctillum and a generalistic predator, Coleomegilla maculata. Studying the nutritional requirements of a generalist versus a specific predator will provide insights on diet development of these 2 organisms. The generalist predator is expected to be an easier target for artificial diet development and success will have greater impact since C. maculate is an important predator of several economically damaging pest species.
3. Progress Report
The first year of the project resulted in a successful establishment of new species of beneficial organisms. Two colonies of the spotted lady bug, Coleomegilla (C.) maculata, of different origins were established using different rearing methods. Five species of stink bugs (Hetereptera: Pentatomidae) were established including Nezara (N.) viridula, Euschistus servus, Acrosternum hilare, and Podisus maculiventris. Work on artificial diets for these organisms yielded promising formulations for C. maculata and N. viridula and significant advances were achieved on developing new rearing methods for all the above species. In the area of lab rearing of C. maculata, extensive literature research on artificial diets and chemical ecology were conducted. Based on the literature and field observations, detailed chemical analyses of prey of the major nutrient groups were conducted. Beetles fed on the diet safely and completed development. Predators collected from the wild can be easily and quickly adapted to laboratory culture on artificial diet because the new diet formulation closely resembles natural prey. Larvae and adult C. maculata collected from the field readily feed on the diet and are able to develop and reproduce. This new discovery opens the door for development of a complete artificial-based rearing system, eliminating the need for greenhouses. On the search for alternative, novel sources of protein that can be incorporated into an artificial diet for C. maculata, preliminary experiments with proteins from marine organisms (microalgae, crustaceans) are yielding promising results. A commonly used protein source for human consumption known as Spirulina algae (in powdered form), in combination with brine shrimp (used as commercial food for tropical fish), provides suitable protein sources that allow efficient development and reproduction of C. maculata in lieu of any insect protein. A new method of refining artificial diets involving nutrient self-selection was tested in Tenebrio molitor (yellow mealworm) with success. In a multiple choice experiment, larvae of the yellow mealworm selectively chose optimal ratios of 2 nutrients. In the area of bio-ecological interactions of plant allelochemicals, spider mites, and its lady beetle predator, Stethorus punctillum, experiments showed that plant chemicals such as linamarin appear to block protein absorption by spider mites. This resulted in negative effects on development time, growth, and body size of the predator.
Riddick, E.W., Rojas, M.G., Morales Ramos, J.A., Allen, M.L., Spencer, B. 2011. Stethorus punctillum (Coleoptera: coccinellidae). Biological Control: A Guide to Natural Enemies in North America. http://www.biocontrol.entomology.cornell.edu/predators/spunctillum.html.