Prediction of insect development in a wheat (Triticum aestivum) silo-bag by computer simulation

RITA ABALONE; ANALÍA GASTÓN; ALIEN ARIAS BARRETO

Dheli

Conferencia; 10th International Conference on Controlled Atmosphere and Fumigation in Stored Products; 2016

CAF Permanent Committee Secretariat

Population growth rates for two insect species, viz. Rhyzopertha dominica (Fabricius) and Sitophilus oryzae (L.), predicted by Driscoll and others, was coupled with a silo bag heat and mass transfer model earlier validated for wheat (Triticum aestivum L.). The rate of populationincrease per week was evaluated as a function of the grain temperature and intergranular relative humidity during storage from summer to winter of dry wheat (13% w.b. and 25°C initial temperature). The wheat was produced in areas with sub-tropical, intermediate and moderateweather conditions. Results showed that the feasibility of insect control by effect of temperature was rather weak for the Central and Southern regions of Argentina, while the rate of population increase per week remained above the unit for the sub-tropical region. To account for the effectof oxygen (O2 ) intergranular concentration on the rate of population increase per week, a very simplified correction factor was proposed to modify Driscoll?s model. Population increase was re-calculated for Rhyzopertha dominica with an initial adult insect infestation of 0.1 and 1 insect/kg. Evolution of insect population, gas concentration, and grain dry matter loss were predicted considering a gas ingress rate of 0.05%? 0.22% O2/d. With 1 insect/kg initial infestation, an atmosphere composition favourable to arrest insect activity was achieved with O2 concentration ranging from 2 to 5%V/V.