Feeding deterrent effects of legume flours against two storage mites, Tyrophagus putrescentiae (Schrank) and Suidasia medanensis Oudemans (Acari:Acaridida)

Abstract

Whole legume flour and its fractions possess a potential in controlling insect pests. Information concerning the activity of various legume flours as bioacaricides against storage mites is rare. Therefore, two kinds of legume flours were obtained from common faba bean (Vicia faba L.) and pea (Pisum sativum L.) seeds to evaluate their effects on growth and development time of two species of storage mites, Tyrophagus putrescentiae (Schrank) and Suidasia medanensis Oudemans via feeding test. The diet was dusted with legume flours at seven concentrations (0, 0.01, 0.1, 0.25, 0.5, 0.75 and 1%). After 21 days, the instantaneous rate of increase (ri) and mortality of both mite species were estimated. There was a significant decrease in (ri) values of both mite populations at concentrations higher than 0.1% of both legume flours. The concentration of 1% faba bean or pea flour was responsible for 100% mortality of T. putrescentiae and S. medanensis. Based on the LD50 and LD90values, pea flour was more toxic to T. putrescentiae and S. medanensis than faba bean flour. Moreover, T. putrescentiae was more sensitive than S. medanensis to legume flours. Development time of the two studied species was considerably prolonged by the addition of bean and pea flours. All tests were conducted under the optimal development conditions of storage mites. The results proved that both faba bean and pea flours possess potent acaricidal activity.