Ground Cover Supplement : GC Supplement - Grain Storage 2005
PEst control 6 inseCT resisTAnCe To phosphine and protectant insecticides is emerging as a serious threat to Australia’s grains industry. The grdC has been sponsoring an Australia-wide program monitoring this resistance to ensure the industry is not caught without adequate means of dealing with storage insects. The grdC ‘resistance Monitoring’ project is led by dr pat Collins, Queensland department of primary industries and Fisheries, Brisbane (northern region), dr rob emery, WA department of Agriculture (western region), and dr Joanne holloway, nsW department of primary industries, Wagga Wagga (southern region). The project covers Australia’s grain regions in a cooperative program that is resistance-testing insect populations in grain storages on farms, in merchants’ premises and in bulk-handling facilities. dr Collins says the development of insect resistance has been caused by sev- eral factors: ¢ Fumigating in unsealed silos, resulting in under-dosing with phosphine, in farm, merchant and bulk-handling storages. This results in frequent exposure of insect pop- ulations to sub-lethal dosages, allowing individuals with a new resistance gene to survive treatment and continue breeding, passing on their resistance. repeat fumi- gations favour the insects that have the resistance gene by allowing them to sur- vive, but kill normal susceptible insects. ¢ repeat treatments with protectant insecticides in the same chemical family, such as organophosphates (for example, fenitrothion, methyl-chlorpyrifos, piri- miphos-methyl, dichlorvos) or synthetic pyrethroids (for example, bioresmethrin). ¢ under-use of other important insect control measures, such as maintaining strict hygiene in and around all grain han- dling and storage facilities and moisture and temperature management in stored grains to reduce insect populations. each year, researchers visit hundreds of farms, grain merchants and bulk-handling sites in each grain region. insect speci- mens are taken at each site and the insects are then bred under controlled conditions in a laboratory. These insects are then exposed to a battery of protectant insecti- cide and phosphine tests. The program has been running since the early 1990s. ThE TrENDs ThAT hAvE EMErGED ArE: ¢ phosphine resistance: the frequency of strong resistance to phosphine is increas- ing in four of the five major insect pest species. This resistance was first detected in 1997. About five per cent of insect populations contain individuals with this strong resistance, which occurs through- out eastern Australia but has not yet been detected in the western grain region. The highest level of resistance occurs in the lesser grain borer (LgB) Rhyzopertha dominica, and we have based our new recommendation for use of phosphine on this LgB resistance. ¢ protectant insecticides resistance: fre- quency of strong resistance to protectant insecticides is increasing. The current sta- tus of pest resistance to protectants is sum- marised in the table below. MANAGiNG rEsisTANCEs ‘ON-fArM’ ¢ Adopt an integrated pest Management (ipM) approach to grain insect control, by close management of moisture content and temperature of grain in storage – the cooler and drier the grain, the less insects like it. ¢ By maintaining strict hygiene standards in grain handling equipment and storage facilities. These non-chemical pest man- agement components greatly reduce the threat from insects and take pressure off protectant insecticides and fumigants in the overall pest management program. ¢ use phosphine appropriately. it is sim- ply impossible with an unsealed storage to ensure adequate phosphine concentration knowing the problem is half the battle kEn bullEn* ExPlAins how insEct rEsistAncE is buildinG, And thE stEPs bEinG tAkEn to kEEP sciEncE And on-fArm PrActicEs on toP of thE ProblEm the frequency of strong resistance to phosphine is increasing in four of the five major insect species throughout eastern australia phillip taylor carries out laboratory testing of grain storage insects for pesticide resistance from hundreds of sites, as part of a grDC- funded project ‘resistance monitoring’.
GC Supplement - Precision Agriculture 2005
GC Supplement - Soil Biology 2005