Preference of and Damage to Processed Cassava Chips by Araecerus fasciculatus (Degeer)

Abstract

Laboratory studies were conducted on the preference and extent of deterioration of differently processed cassava chips caused by A. fasciculatus. The trials were carried at temperature of 25-30oC and relative humidity of 61-92%. Statistical analysis of insect preference to the processed chips in a choice test revealed that adults of A. fasciculatus significantly (p< 0.05) preferred fermented and sun-dried chips to parboiled and plain chips. A susceptibility test and insect developmental study were conducted to further understand the factors responsible for the differences in the processed chips. Weight losses caused by A. fasciculatus on plain, sun-dried and fermented chips across varieties at 79 days of storage were 20.6%, 16.3% and 16.9% respectively. However, parboiled chips sustained lower loss of 2.6%. Adult population density was also significantly lower (P<0.05) on parboiled chips (36.8±2.3) than on fermented chips (108.5±8.6) at 79 days of storage. The developmental period of this pest was similar on all the different processed chips, although it was slightly prolonged on sun-dried chips. The study has shown that parboiling of cassava chips before storage reduces their susceptibility to A. fasciculatus infestation.