INFESTATION AND DAMAGE TO COMMERCIAL SUGARCANE VARZETES FROM SESAMIA SPP. STEMBORERS IN IRAN

SESAMIA stemborers are important constraints on production of sugarcane in Iran, and management is difficult because most activity is hidden inside stems. We determined the impact of stemborers on recoverable sugar and juice contents for six cultivars grown commercially at Karoun Agro-Industrial Company, southwestern Iran, and calculated the impacts for the whole estate. The highest proportion of infested steins was in CP48-103, while the lowest was in ratoon crops of SP71-6163. The highest and the lowest reductions in recoverable sugar content due to stemborer activity were in CP70-321 and SP71-6163, respectively; this translated to the highest loss from reductions in recoverable sugar of 363.2 kg of white sugar per hectare in CP70-321, and the greatest yield loss over the entire estate in CP48-103. The highest and lowest reductions in juice content due to stemborer activity were in SP71-6163 and CP69-315, respectively; this translated to the highest loss from reductions in juice contents of 195.0 kg of white sugar per hectare in SP71-6 163, and the greatest yield loss over the entire estate in CP48-103. Changing the varietal coinposition grown on the estate could have considerable impact on sugar production.