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A comparison of rearing Creontiades signatus distant on green bean pods or pea plants
- Armstrong, J. Scott
- Journal of entomological science 2010 v.45 no.2 pp. 193
- Creontiades, cowpeas, Vigna unguiculata, insect pests, green beans, Phaseolus vulgaris, pods, insect rearing, cotton, Gossypium hirsutum, insect nutrition, ova, nymphs, adult insects, insect development, Texas
- Studies were conducted to determine the most consistent and efficient method for rearing Creontiades signatus based on the number of ova, nymphs and adults produced on green bean pods and cowpeas. For pod rearing, 2 litre cartons with 12 openings on side walls were used. The openings were covered with a piece of cloth glued to the inside of the container. Small slits were cut in the cloth that allowed a green bean pod to be stuck through the opening to serve as both a food and an oviposition substrate. The second method of rearing used whole cowpeas grown in plastic pots in a greenhouse. Plants in the pots were thinned and used as an oviposition and food source. The bugs were enclosed on the plant for the 48 h oviposition period by using a rolled sheet of cellulose acetate to fit inside the pots with ventilation provided by muslin cloth at the top. Once a week, for 12 consecutive weeks, the bean pod containers (12 pods in a container) and peas (3 plants per pot) were infested with 7-day-old female and male C. signatus (20 and 15, respectively). After the 48 h oviposition period, the bugs were removed and the green bean pods and cowpeas were placed in ventilated containers in an environmental chamber. Fresh green bean pods and whole maize were provided to the rearing containers every 3 days. The roots of the cowpeas were gently washed and placed in tubes with hydroponic solution. Five days after the insects were removed, the number of viable ova were identified and counted on the pods and plants by placing a red mark near the operculum. C. signatus ova were inserted into the plant with the operculum nearly level with the oviposition surface. The operculum turned black in 4-5 days when a viable ova matured. After 9 days, the number of live nymphs was counted and, after 16 days, the number of live adults was counted. Results showed that the number of viable ova oviposited on the green bean pods were significantly higher than for the cowpeas, whereas the number of successful nymphs and adults was not significantly different. After 12 weeks, 37% (647) of the total number of ova was oviposited in the cowpeas compared to 63% (1063) of the total number of ova laid on the bean pods. However, the number of nymphs and adults that successfully developed on the cowpeas and green bean pods were comparable. The bean pods shrunk considerably as they were held for egg hatch. This reduced the quality of the pods as an oviposition substrate, resulting in a decrease in the number of ova that matured, eclosed and developed to first-instar nymphs.