Submitted to: Journal of Agricultural and Urban Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2003
Publication Date: 1/1/2003
Citation: Gourdine, J.S., Mccutcheon, G.S., Simmons, A.M., Leibee, G.L. 2003. Kale flower nectar and honey as food sources for enhancing diadegma insulare (hymenoptera: ichneumonidae), a parasitoid of the diamondback moth, plutella xylostella (plutellidae: lepidoptera). Journal of Agricultural and Urban Entomology. 20(1):1-6 Interpretive Summary: The diamondback moth is a serious insect pest of broccoli, collard, cabbage, and other cole crops. Diadegma insulare, a wasp, is a parasite that feeds on and kills the caterpillar of the diamondback moth. These useful wasps are found naturally in and around fields. A study was done to see if kale flower nectar or honey could improve the survival of the wasp and improve its attack on the diamondback moth. The survival of the wasp and its attack on the pest were improved when the wasp was provided diets of kale flower nectar or honey concentrations of 10% or higher. Water or low concentrations of honey were poor diets for the wasp. The results indicate that carbohydrates such as kale flower nectar or honey can increase the performance of the wasp parasite. Modifying fields of cole crops with flowering kale or other types of nectar may benefit growers by improving the effectiveness of the wasp for control of the diamondback moth.
Technical Abstract: The diamondback moth, Plutella xylostella, is a serious pest of cole crops on a global scale, and it is parasitized by Diadegma insulare, a wasp. Field and laboratory tests were conducted to determine the effect of flower nectar of kale, Brassica oleracea L. var. acephala, and honey concentrations on survival and parasitism of D. insulare. Parasitoid survival and rate of parasitism were greater when the wasps were provided 10% honey than when they were provided lower concentrations of honey or just water. Diets of 15% honey and higher concentrations resulted in survival and rates of parasitism which were similar to what was observed when the parasitoids were provided kale flower nectar. The results indicate that kale flower nectar or honey as sources of carbohydrates can increase the survival and rate of parasitism by D. insulare. Manipulating the agroecosystem with kale flowers or other nectar sources may benefit growers by enhancing the effectiveness of control of the diamondback moth in cole crops by this parasitoid.