Fourth International Bemisia Workshop International Whitefly Genomics Workshop
Bemisia tabaci (Homoptera: Aleyrodidae) Instar Preference by the Parasitoids Eretmocerus mundus and Encarsia pergandiella (Hymenoptera: Aphelinidae)
1 Beneficial Insect Research Unit, Kika de la Garsa Subtropical Agricultural Research Center ARS-USDA, Weslaco, TX, USA. Correspondence: sgreenberg@weslaco.ars.usda.gov
2 Current address: European Biological Control Laboratory ARS-USDA, France
3 Texas Agricultural Experiment Station, Texas A&M University, Weslaco, TX USA
Studies were conducted to compare preference among Bemisia tabaci Gennadius biotype B instars for parasitization by Encarsia pergandiella Howard and Eretmocerus mundus Mercet under no choice and two and four instar choice experiments. In the no choice treatment, E. mundus was more successful in parasitizing the younger host instars, while E. pergandiella was more successful in parasitizing the older instars. When parasitoids females were presented six different pair combinations of a two instars at a time, parasitism by E. mundus was always greatest in the youngest of any of the two-instar combinations, except when first (29.2%) and second (31.0%) instars were presented together. Parasitism by E. pergandiella was always greater in the older instars, except significantly more third instars were parasitized when present with fourth instars. When equal numbers of all four host instars were provided simultaneously, the number of first, second, and third instars parasitized by E. mundus was not significantly different between each other (range: 10.3–16.4%), but four instars were parasitized at a significantly lower rate (2.1%). When E. pergandiella were presented with all four instars, parasitization was significantly highest in third instars (17.2%), and lowest in first (2.8%). Thus, each parasitoid species possesses a different range of instar preferences for reproduction. The present results provide additional important information toward explaining elements of interspecific interactions, and combined with ongoing research, should lead toward more efficient use of parasitoids to manage whiteflies.
|
PREVIOUS Pest Situation and Biological Control of Bemisia tabaci in Canary Islands |
NEXT Novel Technique for the Control of Insect Growth Regulator Resistant B-Biotype Bemisia Tabaci in Australia |