Comparative Demography of the Spider Mite, Oligonychus afrasiaticus, on four Date Palm Varieties in Southwestern Tunisia

The date palm mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae), is a serious pest of palm date fruits. Life cycle, fecundity, and longevity of this mite were studied on fruits of four date palms, Phoenix dactylifera L. (Arecales: Arecaceae)(varieties: Deglet Noor, Alig, Kentichi, and Besser), under laboratory conditions at 27 = 1 °C, 60 ± 10% RH. Total development time of immature female was shorter on Deglet Noor fruits than on the other cultivars. O. afrasiaticus on Deglet Noor had the highest total fecundity per female, while low fecundity values occurred on Besser. The comparison of intrinsic rates of natural increase (rm), net reproductive rates (Ro), and the survival rates of immature stage of O. afrasiaticus on the host plants suggests that O. afrasiaticus performs better on Deglet Noor fruits. The mite feeding on Alig showed the lowest intrinsic rate of natural population increase (rm = 0.103 day 1). The estimation of difference in susceptibility of cultivars to O. afrasiaticus is crucial for developing efficient pest control programs. Indeed, less susceptible cultivars can either be left unsprayed or sprayed at low threshold

Control of cereal aphids on wheat in People's Democratic Republic of Yemen

AbstractLoss estimates for wheat insects in Africa and Asia have not received adequate attention. However, in PDR of Yemen, pests including insects, diseases, weeds and birds can cause 10™70% loss of wheat crop. Aphids are considered to be the major insect pests of wheat in the country. A survey of indigenous natural enemies has shown that they may contribute to overall aphid control. Sowing date experiments have shown that sowing in November led to higher yields and lower insect infestation than sowing in October and December. The insecticides tested achieved a significant control of aphids and higher yields when compared with unsprayed plots. A single application of malathion or dimethoate before mid-January was recommended for chemical control.</jats:p

EFFECT OF CEREAL APHID INFESTATION ON GRAIN YIELD AND PERCENTAGE PROTEIN OF BARLEY, WHEAT, AND OATS IN SOUTHWESTERN QUEBEC

AbstractNatural infestations of cereal aphids caused significant reductions in grain yield in field plots of early and late cultivars of barley, wheat, and oats in southwestern Quebec. Severely reduced grain yields resulted when caged plants of wheat and late cultivars of barley and oats were artificially infested, but early cultivars of barley and oats were less affected. The percentage protein of grain was significantly reduced in all crops, but wheat and late oats were most affected.</jats:p