EFFECT OF CERTAIN AGRICULTURAL PRACTICES AND NON-CHEMICAL MATERIALS ON INSECT PESTS, PREDATORS AND YIELD OF ROSELLE PLANTS IN MINIA REGION

The effect of plant variety, planting date and hoeing of roselle plants on the occurrence of certain insect pests and their associated predators were studied during the two successive seasons of 1997 and 1998 in Minia Governorate. Also, the efficiency of some non-chemical materials against the main sucking pests on roselle during a third season (1999) was evaluated under field conditions.
                During the whole season (in both 1997 and 1998), four sucking insects were found commonly infesting roselle leaves, i.e. Empoasca spp.; Bemisia tabaci; Thrips tabaci and Lygus spp. Moreover, duringfruiting stage, Earias insulana and oxycarinus hyalinipennis were also found to infest roselle bolls. Two common predators, i.e. Coccinella undecimpunctata and Orius spp. were recorded and associated with the sucking pests. Generally, Baladi variety proved to be more favorable to the sucking pests (including O. hyalinipennis) than Sabahia 17. Meanwhile, the latter variety was highly attacked by E. insulana than the first. Also, it was evident that the peak of the predators coincided with that of the sucking mixed pests infesting roselle plants, especially during the period from July till September. In addition, roselle plants (Sabahia 17) cultivated on the 2^nd and 3^rd planting dates (22^nd April and 2^nd May, respectively) relatively harboured more sucking pests than those of the 1^st planting date (12^th April). Hoeing (Baladi variety) had slightly reduced the number of the sucking insect pests in both growing seasons. The yield of sepals for Sabahia 17 was markedly higher than for Baladi, and this was accompanied by higher infestation of sucking pests on Baladi than Sabahia 17. The yield was also affected by planting date, where the highest yield of sepals and the lowest number of sucking pests were recorded for the earlier (12^th April) cultivation of Sabahia 17. A similar trend was recorded for the treatment of hoeing of Baladi variety.
                In the third season during 1999, soft soap and the microbial (fungal) preparations were effective against Empoasca spp. and B. tabaci, while soft soap and the mineral oil Capel 2 were effective on the Lygus spp. and O. hyalinipennis.