Studies on biology and ecology of Galeatus scrophicus Saunders (Hemiptera: Tingidae) in Sudan

Among insect fauna reported in Sudan, Galeatus scrophicus Saunders, was detected earlier in last century, and known as a pest of sunflower. Nevertheless, very limited research works have yet been conducted on this pest. Therefore, this study was proposed to cover certain bio-ecological aspects of G. scrophicus, including host range, geographical and intra-host distributions, seasonal abundance and life cycle of pre-adult stages. Such parameters were fulfilled through surveys, field experiments and laboratory works. The results revealed seven host plants for the pest under the family Compositae, viz., Helianthus annus L., Lactuca sativa L., Lactuca taraxifolia (Willd.) Schumach, Sonchus cornutus Hochst. Ex Oliv.+ Hiern, Sonchus oleraceus L., Xanthium brasilicum Vell. and Pluchea diosecoridis (L.) DC., all of them, except the former species, were new records. Higher numbers of nymphs and adults were reported on the upper surfaces than on the lower sides of plant leaves. However, the pest was found in all sunflower areas in central Sudan. The seasonal counts showed that the highest population of the pest occurred in winter as compared with autumn season. On the other hand, the mean total durations of pre-imaginal stages were shorter in autumn (14.12 ± 0.15 days) than in winter (25.27 ± 0.26) season. Therefore, some detrimental factors that seem to suppress the pest population buildup in autumn were suggested, and recommended for additional studies so as to design appropriate ecologically sound control measures.