The action of phosphine against the eggs of phosphine-resistant and -susceptible strains of Rhyzopertha dominica F.
The effect of phosphine at exposure periods of 24, 48 and 120 h on hatching and mortality of 0- to 1-day-old eggs of susceptible (TN6) and resistant (FC10) strains of Rhyzopertha dominica of field origin was investigated. The fumigant affected hatching in both the strains. In a 48-h exposure at 27 (+/- 2) degrees C, the LD99 doses for the eggs of TN6 and FC10 were 0.56 and 3.25 mg litre-1, respectively. Significant reduction in hatching was observed in treated batches with progressive increase of phosphine dose in the first 2-3 days. On subsequent days the numbers hatching were often similar to those in controls, and sometimes exceeded control hatch, especially following a 5-day exposure. A critical change in the order of susceptibility of egg and adult stages of the two strains was noticed. In 48-h exposures, eggs of the susceptible strain were more tolerant than their adults, whilst the reverse was true in the resistant strain.
Rajendran
S
S
Food Protectants and Infestation Control Department, Central Food Technological Research Institute, Mysore-570 013, India.
Nayak
K R
KR
Anjum
S S
SS
D000818:Animals; D001517:Coleoptera / Q000145:classification / Q000187:drug effects*; D005260:Female; D007305:Insecticide Resistance / Q000502:physiology; D007306:Insecticides / Q000633:toxicity*; D010063:Ovum / Q000187:drug effects*; D010720:Phosphines / Q000633:toxicity*; D013997:Time Factors
D007306:Insecticides; D010720:Phosphines