EFFECT OF SOME PHYSIOLOGICAl AND MORPHOLOGICAL FEATURES OF SOME PEAR VARIETIES ON THE BIOLOGY OF THE LACE PEAR BUGS

Abstract

The study of the effect of some physiological and morphological features of some pear varieties Zafarania, Othmani, Le-Conte and Calleryana on biology of the lace pear bug showed that the average number and length of small hairs per ml2 have an effect on the average number of eggs per female. The number of eggs laid was 142.4 egg per female on Le-Conte variety which has surpassed other varieties in the average number of small hairs whose length was the least. Females were not able to lay eggs on Calleryana variety as its leaves were void of small hairs. There has been a significant difference between pear varieties in the average number of osmic pressure; which were 20.7, 20.4 atmospheric pressure Zafarania and Othmani varieties respectively. While they were significantly different with Le-Conte and Calleryana varieties whose have 19.6, 25.5 atmospheric pressure respectively. Results have shown that the water content was accompanied by an increase in egg's number. An increase in the osmic pressure resulted in a decrease in the eggs laid number compared to the Calleryana variety with low water content and high osmic pressure, where females have laid no eggs on its leaves. Results have also shown a different effect of water content and osmic pressure upon other insect's biological features depending on pear variety. The study has shown that the decrease of chlorophyll, carotene and lipids in Calleryana in the leaves an inhibit the growth and biogenesis of the insect on its leaves compared to other pear varieties. The results also exhibited a superiority of Le-Conte variety in the average increase of insect with 0.20% compared to Zafarania and Othmani variety where it has reached 0.182% and 0.186% respectively, and were significantly different from Calleryana variety.