C. Vidal et S. Kreiter, RESISTANCE TO A RANGE OF INSECTICIDES IN THE PREDACEOUS MITE TYPHLODROMUS-PYRI (ACARI, PHYTOSEIIDAE) - INHERITANCE AND PHYSIOLOGICAL-MECHANISMS, Journal of economic entomology, 88(5), 1995, pp. 1097-1105
Two strains of Typhlodromus pyri Scheuten were studied to investigate
physiological and genetic patterns of resistance to several insecticid
es. Results revealed resistance to a range of insecticides (carbamate,
organophosphate, and pyrethroid). This species may thus have a promis
ing future in integrated pest management programs in various crops. In
heritance of resistance to an organophosphate using conventional techn
iques (crosses/backcrosses) indicated polygenic resistance to parathio
n methyl, a common phenomenon in laboratory-selected strains but rare
in wild strains. Release of mites with polygenic resistance in the fie
ld might lead to hybridization with susceptible migrants, thus making
resistance mechanisms unstable. However, Fl females (hybrid females) w
ere more resistant than R females and resistance levels in the 2 types
of Fl females were different. Such higher resistance in hybrid female
s could be explained by a heterosis effect (associated with a compleme
ntation phenomenon). We used 2 synergists (DEF and piperonyl butoxide)
to define the physiological mechanisms of resistance to parathion met
hyl and fenvalerate. Results seemed to indicate that neither ester-lin
k hydrolysis nor oxidative degradation of insecticides has a critical
role in resistance to. parathion methyl. Tests done with fenvalerate s
uggest that oxidative degradation and, to a lesser extent, hydrolytic
reactions are partially involved in the mechanisms of resistance to th
is pyrethroid. Overall results are discussed in terms of basic researc
h (genetic) and agronomic applications (for example, improved resistan
ce management, strain selection with resistance genes).