Oviposition was greatest at 25°C, with a total oviposition of 287.4 eggs per female and a mean oviposition rate of 22.4 eggs per female per day. By continuing you agree to the use of cookies. Two release methods were compared: dried N. fresenii-infected cotton aphid “cadavers” and chamber inoculation of A. gossypii. gossypii population dynamics in cotton.

Temperature and food quantity are two major factors affecting C. septempunctata population growth. The first experiment addressed the effect of five temperatures (15, 20, 25, 30 and 35 ± 0.5°C) on the beetle bionomics, while the second one addressed the effect of food quantity on the beetle bionomics at a temperature of 25°C. gossypii obtained its greatest intrinsic rate of increase (0.386 d -1) at 25°C. The relationship of temperature with the relative mortality rate of each pre-oviposition stage and each adult age class was described with parabolas. Augmentation of the seven-spot beetle by intercropping cotton with wheat is the most commonly used approach for cotton aphid biological control. Handling rate increased with 50-100% from one predator stage to the next, but it was somewhat similar in the fourth instar and adult predators. Immigrating numbers of seven- spot beetle adults is the key factor.

Based on the model of Chapter 5, a simulation model of the spatio-temporal dynamics of the coccinellid-aphid system in cotton-wheat intercropping was developed in Chapter 6. Threshold temperatures for development of eggs, larvae, pupae and adults ranged from 10.9 to 13.9°C, with 12.6°C for the entire life span; and thermal constants were 42.0, 103.7, 63.6 and 302.9 D°, respectively. These results suggest that it is possible to increase distance from wheat to cotton strips in the current intercropping system and maintain effective biological control of the cotton aphid.

Based on models developed and insights gained in this study, a promising strategy of cotton-wheat strip cropping was proposed, which would be not only favorable for A. N. fresenii persisted and spread in the aphid population until early October 1994 and late September 1995. Life history parameters of the seven-spot beetle feeding on A. Biological control of cotton aphid (Aphis gossypii Glover) in cotton (inter)cropping systems in China : a simulation study: Author(s) Xia, J. Handling rate towards early instar, late instar and adult prey varied with a ratio of about 3:2:1. Go back to site navigation, http://library.wur.nl/WebQuery/wurpubs/37855, Biological control of cotton aphid (Aphis gossypii Glover) in cotton (inter)cropping systems in China : a simulation study, biologische bestrijding, insecten, nuttige insecten, katoen, Aphididae, Coccinellidae, gemengde teelt, tussenteelt, meervoudige teelt, tussenplanting, computersimulatie, simulatie, simulatiemodellen, China, Aphis gossypii, Coccinella septempunctata, Biologische bestrijding van plagen, biological control, insects, beneficial insects, cotton, mixed cropping, intercropping, multiple cropping, interplanting, computer simulation, simulation, simulation models, Biological Control of Pests. @article{300934c52ba149d8b5390236cf7b4e8d. gossypii were determined in two experiments in the laboratory (Chapter 3). The highest mean percentage infection in the cadaver treatment in 1994 reached a level (14%) considered imminent for epizootics (12–15%). Search rate increased with 50-100% from one larval predator instar to the next but decreased from the fourth instar to the adult predator. Development of A. High relative rate of population increase at 25°C resulted in a daily population increase of 47% and a doubling time of 1.8 d, illustrating the tremendous growth capacity of A. The resulting annual losses amount to 10-15% of the attainable yield. Thesis Landbouwuniversiteit Wageningen. In August 1994 and 1995 classical biological control releases were made in cotton in the San Joaquin Valley, California, with an Arkansas strain of the entomopathogenic fungus, Neozygites fresenii, a pathogen of the cotton aphid, Aphis gossypii.Pre-release samples in both years indicated that N. fresenii was not naturally present in A. gossypii populations in the San Joaquin Valley. All functional responses were of type 11 and were adequately described by Rogers' random predator equation. : s.n.] There is, therefore, a demand for developing more sociologically, economically and ecologically sound cotton-wheat intercropping systems. The simulated and observed data were in reasonable agreement at all levels, though discrepancies increased with the level of scale. doi = "10.1111/j.1439-0418.1992.tb01140.x". Over the range of prey densities tested, a 3.54-fold increase in prey density resulted in a 2-fold reduction in larval development time and a 3-fold increase in larval survival. septempunctata-A. gossypii biological control but also advantageous with respect to labor requirement, fiber and seed quality, and suppression of the cotton bollworm and verticillium wilt by cultural practices. In August 1994 and 1995 classical biological control releases were made in cotton in the San Joaquin Valley, California, with an Arkansas strain of the entomopathogenic fungus, Neozygites fresenii, a pathogen of the cotton aphid, Aphis gossypii.