Serological Studies on the Relationship between Some Egyptian Clover
Insect Pests and Their Predators

• H.A. Boraei,* Asmhan E. Youssef,* E.M. El-Kady,** and A. A. Farag***
• * Econ. Entoml. Dept. Fac. of Agric. Kafr El-Saheikh Tanta Univ., Egypt.
• ** Agric Botany. Dept. Fac. of Agric. Kafr El-Saheikh Tanta Univ., Egypt.,
• *** Plant protection Research Institute, Sakha, Agric. Res. Station.
• The Third International Conference onIPM Role in Integrated Crop management and Impacts on Environment and Agricultural Products. 26-29 November 2005, Giza, Egypt

Abstract

In the present work prey-predator relationships had been studied by three methods; analyzing statistically the correlation between population fluctuations of both groups; evaluating the feeding efficiency of the predators in the laboratory and studying the possibility of using serology in this respect. Throughout the two years of the study (2001-2003), at the experimental farm and Econ. Entomol. Dept. of Kafr El-Sheikh Faculty of Agriculture, it was found that the lacewing predator Chrysoperla carnea Steph. Swarmed twice a year, the first peak (22 individ.) which occurred in Dec. followed the appearance of Aphis gossypii Golve and Spodoptera littoralis Boisd at the beginning of the season. The second peak which occurred in Feb. or Mar. (19 individ.) synchronized with the peaks of the alfalfa weevil, the green bug, aphids and the leafhoppers. Highly significant correlation was detected between that predator and the alfalfa weevil.

The ladybird Coccinella undicempunctata L. was found to occur in two peaks. The first was observed only in Dec. (8 individ.) coincided with A. gossypii and S. littoralis. However, the second peak occurred in Mar. (40 individ.) coincided with the alfalfa weevil, aphids and the leafhoppers, with high positive correlation recorded for them.

The three larval instars of Ch. carnea required duration of 7.75, 8.35, 8.45, and 9.80 days to develop to pupation on the cotton leafworm larvae, cotton leafworm eggs, alfalfa weevil larvae and the aphids, respectively. During all the larval stage, it consumed 83.50, 425.5, 88.o5, and 336.50 individ., not less than 50% of them were consumed by the 3rd instar solely (55.69, 77.44 57.99, and 50.89%), respectively. The ladybird predator devoured 694.00 of the cotton leafworm eggs during the shortest duration of larval stage (8.25 days). However, the less individuals it consumed from other insect pests of clover field (329.75 aphids, 229.75 cotton leafworm larvae, and 149.oo alfalfa weevil larvae), the longer duration periods were (8.30, 11.75, 13.45 days), respectively. The 4th instar consumed relatively the highest percentages of individuals offered for the four mentioned insects, as it consumed 42.95, 37.76, 5o.05 and 49.83%, respectively. Serological studies carried out to evaluate the relationship between the antiserum of two predators, Ch. carnea and C. undecimpunctata against insect pests antigens the degree of reaction shown in the agar of the double diffusion test. Results of double diffusion test revealed strong reactions detected for the larvae of the cotton leafworm (6 lines) indicated that it might be the most acceptable prey by the predator, Ch. carnea followed by aphids (4 lines) and the alfalfa weevil (3lines). Sharp reaction observed between the predator, C. undecimpunctata antiserum and the aphids (6 precipitin lines) and the cotton leafworm (4 lines). Reactions were less detectable with the other heterologous antigens. It is worthily mentioning that both of the two antisera when tested with the antigens of the other predators, no reactions were detected. Finally those results suggest that serological techniques might be used in detecting the relationship between the predators and the insect pests, the precise and quick method which now widely used in insect researches and rarely used in Egypt.