CONTRIBUTIONS TO THE STATUS OF SUGAR-CANE INFESTATION WITH THE PURPLE-LINED STEM BORER Chilo agamemnon Bles., (LEPIDOPTERA : PYRALIDAE) JUST PRIOR MILLING

In Middle and Upper Egypt, sugar-cane plants are subjected to infestation with the Purplelined stem borer, Chilo agamemnon Bles.(Lepidoptera: Pyralidae).This paper contributes to the pest's status on sugar-canes of the commercial variety "GT.54/C-9" just prior milling in 4 milling factories.Aspects considered throughout two successive milling seasons (1996 & 1997) were the rate of infestation in El-Minia, Souhag and Quena Governorates, the rate of infestation on plant-cane, 1 st , 2 nd , and 3 rd ratoon plantations, the distribution of infestation on the different parts of sugar-cane stalk and stalk breakage.The highest rate of infestation occurred in Souhag and the lowest rate took place in El-Minia while the rate of infestation in Quena was slightly higher than it in El-Minia but comparatively less than in Souhag.Plant cane was the most susceptible plantation and the 3 rd ratoon was the least susceptible plantation while the 1 st and 2 nd ratoon canes were subjected to intermediate infestation rates.Infestation was concentrated at the lower and middle thirds of the stalk.Roughly, about one third of the infestation took place on the lower third of the stalk and about one half of it occurred on its middle third whereas less than one sixth of the infestation was recorded on the upper third of the stalk.Stalk breakage occurred anywhere along the stalk but it mostly happened at the upper third and to a relatively less extent at the middle third while it rarely took place at the lower third of the stalk.