Efficacy of grain protectants against four psocid species on maize, rice and wheat.
BACKGROUND
Psocids are emerging pests in stored products, particularly in amylaceous commodities such as grains. Currently, their control is based on the use of fumigants and contact insecticides; however, newer data indicate that psocids are tolerant to insecticides used to control other stored-grain species. This study evaluated the insecticides registered in the USA for use on stored maize, rice and wheat for control of the psocid species Lepinotus reticulatus, Liposcelis entomophila, L. bostrychophila and L. paeta. Mortality of exposed adult females was recorded after 7 and 14 days of exposure, while progeny production was assessed after 30 days of exposure.


RESULTS
On wheat and rice, chlorpyriphos-methyl + deltamethrin was generally more effective against exposed parental adults than spinosad or pyrethrin, while pirimiphos-methyl was more effective on maize than spinosad or pyrethrin. In most cases, progeny production was suppressed in the treated grains. Progeny production was consistently lowest on wheat and rice treated with chlorpyriphos-methyl + deltamethrin and maize treated with pirimiphos-methyl.


CONCLUSIONS
Chlorpyriphos-methyl + deltamethrin and pirimiphos-methyl were the most effective insecticides for all species and commodities. Conversely, efficacy of spinosad or pyrethrum was highly dependent on the psocid species and commodity.
Athanassiou
Christos G
CG
USDA-ARS Grain Marketing and Production Research Center, 1515 College Avenue, Manhattan, KS 66502, USA. athanas@aua.gr
Arthur
Frank H
FH
Throne
James E
JE
D000818:Animals; D005260:Female; D005519:Food Preservation; D007313:Insecta / Q000187:drug effects*; D007306:Insecticides / Q000494:pharmacology*; D008297:Male; D012275:Oryza / Q000469:parasitology; D014908:Triticum / Q000469:parasitology; D003313:Zea mays / Q000469:parasitology
D007306:Insecticides