Production Of Biological Control Agents Research Articles

Modeling adult emergence and fecundity of factitious hosts under different food sources supports massive egg production management.

Ephestia kuehniella (Lepidoptera, Pyralidae) and Sitotroga cerealella (Lepidoptera, Gelechiidae) are important factitious hosts used for production of biological control agents. Their differences in terms of biology and behavior require adjustments in their mass production, particularly when using corn or barley as food in grain or in bran. We modeled adult emergence, oviposition period and egg production along time after emergence, as a function of the food source. Significant differences between hosts or food type were found for these variables and for adult weight but not for sex ratio. Our results confirm the possibility of mass production of these hosts using corn or barley as food source. Integrating adult emergence patterns and age specific fecundity patterns into a single model, it is clear that rearing E. kuehniella on barley would result in the highest egg output in much shorter time than E. kuehniella on corn or S. cerealella on barley.

Cold storage affects mortality, body mass, lifespan, reproduction and flight capacity of Praon volucre (Hymenoptera: Braconidae)

The possibility of storing natural enemies at low temperatures is important for the mass production of biological control agents. We evaluated the effect of different periods of cold storage on immature mortality, mummy body mass, lifespan, reproduction and flight capacity of the parasitoid Praon volucre (Haliday). One-day-old mummies of the aphid Macrosiphum euphorbiae (Thomas) containing pre-pupae of P. volucre were stored in a climatic chamber at 5°C and 70 ± 10% RH in the dark for different periods of time (5, 10, 15 and 20 days). The control consisted of mummies kept at 22 ± 1°C, 70 ± 10% RH and a 12 h photophase. Percentage adult emergence, mummy body mass, flight capacity and number of eggs in the ovarioles of P. volucre females decreased with increase in the period of storage, while the longevity of females was only slightly affected. Fat content of mummies, percentage of parasitized aphids and survival of progeny to emergence decreased with increase in the period of storage. Storage of P. volucre pre-pupae for up to 5 days at 5°C did not affect any of the above mentioned parameters. The fact that P. volucre pre-pupae can be stored for 5 days without loss of quality and for 10 days with only a slight loss facilitates the planning of mass production and shipment.

METAMASIUS CALLIZONA (COLEOPTERA: DRYOPHTHORIDAE): LONGEVITY AND FECUNDITY IN THE LABORATORY

Metamasius callizona (Chevrolat) is native to southern Mexico and Guatemala. It was detected in Broward County, Florida, in 1989 and has spread to 20 counties in southern Florida, where it devastates populations of native epiphytic bromeliads and also attacks cultivated bromeliads. Larvae mine into stems of larger bromeliads, killing them. New data were obtained at ≈25°C and a photoperiod of 14:10 L:D to optimize cultures of this insect to serve as hosts for the production of biological control agents. After pairing with males, it took an average of 28.9 d (±17.8, range 8-89 d) for females to begin laying eggs; thereafter, each female laid eggs for the remainder of her life, or within just a few days of her death. The total duration of life of 75 ovipositing females averaged 156.4 d (±96.7, range 26-387 d); their lifetime egg production averaged 39.6 eggs (±40.0, range 2-188 eggs).

Influence of bacteria isolated from rice plants and rhizospheres on antibiotic production by the antagonistic bacterium Serratia marcescens strain B2

Serratia marcescens strain B2 is an antagonistic bacterium that produces the red-pigmented antibiotic prodigiosin and suppresses rice sheath blight caused by Rhizoctonia solani AG-1 IA. Rice sheath blight disease was suppressed when plants were inoculated with this bacterium an hour before pathogen inoculation but not when plants were treated 4 weeks before pathogen inoculation. In both cases the bacteria were detected in the rice rhizosphere 4 weeks after inoculation. Bacteria isolated from the rice plant and rhizosphere inhibited biosynthesis of prodigiosin in S. marcescens strain B2. We suggest that bacteria isolated from rice plants and rhizospheres mediate the suppression of antibiotic production of biological control agents and that such suppression is common under field conditions.

Temperature-Dependent Effects on Development, Mortality, and Growth ofHippodamia convergens(Coleoptera: Coccinellidae)

Insect natural enemies selected for specific traits such as faster developmental times, higher survivorship, increased fecundity, and larger body size might be considered during production of biological control agents in certain situations. For instance, traits related to developmental rates may be selected for if genetically based variation exists within temperature-dependent responses. We compared preimaginal development, mortality, and size of Hippodamia convergens Guerin-Meneville at 4 constant temperatures (18, 22, 26, and 30°C). Total preimaginal development ranged from 51 d at 18°C to 14 d at 30°C. Developmental times were significantly different among isofemale lines of field-collected H. convergens from Oregon at all temperatures tested (18, 22, 26, and 30°C). Variation within female lines was significant only at 26°C. The lower developmental thresholds for egg, larval, and pupal stages were 9.9, 13.7, and 14.5°C, respectively. Degree-day (DD) requirements for development were 58.8, 166.7, and 52.6 for eggs, larvae, and pupae, respectively. Total preimaginal development required 231 DD above a temperature threshold of 13.6°C. Degree-day requirements for 14 field-collected female lines varied from 223 to 273, whereas the lower threshold for development ranged from 13.1 to 13.8°C. Mortality decreased with increasing temperatures. At the lower temperature (18°C), higher mortality occurred during the 4th instar and pupa. Pupal and adult weights differed across temperatures. Heavier pupae and adult beetles were reared at 22°C. Also, wings were larger among beetles reared at 22°C. The development, mortality, and size measurements provide data for establishing suitable rearing conditions for future studies on the ecology of H. convergens.

Genetic Problems in the Production of Biological Control Agents

Genetic Problems in the Production of Biological Control Agents