Raju R. Pandey

Impact of avian and arthropod predation on lepidopteran caterpillar densities and plant productivity in an ephemeral agroecosystem

Abstract.  1. Most studies evaluating the combined impact of spiders and other predators on herbivore densities in agroecosystems have focused primarily on their trophic connections with invertebrate predators (e.g. carabids, chrysopids); however linkages among spiders and vertebrate predators may also help structure the population dynamics of insect herbivores. A field experiment was conducted to examine the impact of avian and spider predation on lepidopteran caterpillar densities and plant productivity within a Brassica agroecosystem.

Weeds Adjacent to Hawaiian Pineapple Plantings Harboring Pink Pineapple Mealybugs

Abstract Surveys were conducted to identify the weeds bordering Hawaiian pineapple plantings that could serve as hosts for the pink pineapple mealybug, Dysmicoccus brevipes (Cockerell). Collected mealybugs were held to determine parasitization by the encyrtid Anagyrus ananatis Gahan. Greater than 15 species of weeds were found around pineapple plantings in both disturbed (e.g., mowed, herbicide treated, manual weed removal) and undisturbed areas. Weed diversity was low in the undisturbed areas with guinea grass, Panicum maximum, being the dominant species and free of pink pineapple mealybug. Weed species composition was more diverse in the disturbed areas adjacent to plantings, with routinely mowed areas being more diverse. Although pink pineapple mealybug is a polyphagous mealybug, it was only found in moderate densities on rhodesgrass, Chloris gayana, and wire grass, Eleusine indica, both of which were found in mowed and unmowed weedy areas with the former species being more common. All phenological stages of rhodesgrass were infested with pink pineapple mealybugs, but only mature wire grass plants were infested. None of the pink pineapple mealybugs collected from the weeds produced parasitoids, which suggests that the most common weeds found during these studies did not serve as reservoirs for A. ananatis. Because some common weed species harbored Dysmicoccus mealybugs, weed management could play a significant role in reducing pink pineapple mealybug movement into pineapple plantings.

Enhanced production of pink pineapple mealybug, Dysmicoccus brevipes (Hemiptera: Pseudococcidae)

Abstract A mass rearing program was developed for the pink pineapple mealybug (PPM), Dymsicoccus brevipes (Cockerell) (Hemiptera: Pseudococcidae), to provide host material for producing the encyrtid parasitoid Anagyrus ananatis (Gahan). PPM individuals produce honeydew that accumulates on heavily infested squash and entraps crawlers and older instars. A new protocol was tested to reduce accumulated honeydew with minimal mortality to PPM. Butternut and kobocha squash were placed in rearing containers and covered with coarse vermiculite (>2.36 mm diameter) after being infested with PPM. Use of vermiculite removed the honeydew from the squash surface. PPM produced using vermiculite were easily harvested from the host squash, but mealybugs produced on squash without vermiculite were embedded within the honeydew. When individual kobocha squash fruit were inoculated with 300–400 mature PPM adults (>0.6 mm length), about 700 adult PPM (appropriate for A. ananatis production) were produced for each dollar value (USA) of squash fruit (i.e., ∼1500 PPM per individual squash).