Parasitism of Bollworm (Lepidoptera: Noctuidae) Eggs on Nectaried and Nectariless Cotton

Understanding and Manipulating Plant Attributes to Enhance Biological Control

“…Significant reductions in predator populations were found in fields planted with varieties lacking extrafloral nectaries (Schuster et al, 1976;Adjei-Maafo and Wilson, 1983). An important decline in the parasitism of H. zea by the egg parasitoid Trichogramma pretiosum Riley was also found in the same crop (Treacy et al, 1987).…”

Responses of Microplitis croceipes to host and nonhost plants of Heliothis virescens in a wind tunnel

“…Although consistently low levels of parasitization by Trichogramma pretiosum Riley were reported on Heliothis eggs in nectariless cotton, the data failed to show any significant difference in parasitization on nectaried cotton (Treacy et al, 1987). The use of extrafloral nectaries as an alternative food source by predatory and parasitic insects when host populations are low has been suggested by Calderon (1977) and Yokoyama (1978).…”

Genetically Modified Crops and Biological Control with Egg Parasitoids

“…These changes may affect biological control by egg parasitoids if nectar production is modified in an ecologically significant manner in GM crops (cf. Treacy et al 1987). …”

“…Such trait changes are not rare and cannot be assumed inconsequential, so should be examined for their influence on GM crop-egg parasitoid interactions. It is tempting to predict, for example, that increased nectar and honeydew production should contribute to enhancing parasitism rates by egg parasitoids, particularly in light of evidence that both nectar and honeydew availability enhance biological control by and reproductive parameters of Trichogramma and other egg parasitoids (Treacy et al 1987, Heimpel and Jervis 2005, Romeis et al 2005, Fuchsberg et al 2007, Wäckers et al 2008. In other cases, however, negative impacts of phenotypic trait changes on egg parasitoids could be predicted, such as greater exposure to GM crop proteins if production of honeydew and nectar are enhanced; thus, the potential impacts of such trait changes should also be examined closely.…”

“…Degenhardt et al 2003, Colazza et al 2004, Fatouros et al 2008, or enhanced nectar production, including varieties with extra-flora nectaries, to enhance pest parasitism rates by egg parasitoids (cf. Treacy et al 1987, Picard-Nizou et al 1993, 1995, Tesoriero et al 2004, Heimpel and Jervis 2005. Finally, other opportunities involve deploying host plant resistance based on GM crop proteins more rationally, so that their use is more sustainable and compatible with IPM strategies than has hitherto been the case.…”