Insect Pest Management in Stored Grain

Once cereal grain is harvested and put into storage, it provides a resource for a range of insect pests of stored grain. With few exceptions, these insects rarely attack grain in the field before harvest, but once the grain is in storage there is a degree of inevitability that insect infestation will occur. This means that methods are needed to either disinfest grain or to protect it from infestation during storage. The aim of this chapter is to review recent advances in insect pest management in stored grain, ranging from methods that are well established to those that are still being evaluated. This topic has been the subject of considerable laboratory and field research as evidenced by the large and growing body of published studies. Resistance to phosphine resistance and various insecticides, as well as the phase-out of methyl bromide as an ozone-depleting substance, continue to be major drivers for research on management of insects in stored products. Other research has focussed on improving the basic understanding of various methods or ways of improving methods currently in use. Despite extensive research on a wide variety of chemical and non-chemical treatments, very few have been commercialised. Two examples are spinosad, which has been registered as a grain protectant, and sulfuryl fluoride, which is now available as a grain fumigant. The interest in non-chemical treatments, especially aeration cooling, is encouraging. In general, integrated pest management is seen as the goal of entomologists, requiring the strategic integration of multiple methods to provide maximum effect with minimal health and environmental risks. Some of the chemical and non-chemical treatments reviewed in this chapter have great potential to be used as part of an integrated approach

Insecticide Resistance

Insecticides, including contact chemicals and fumigants, are essential components of the majority of stored product protection systems. Their use enables the implementation of effective quarantine systems, ensures food security and facilitates domestic and international trade. Insecticides have many advantages. They can be integrated easily into grain handling logistics; they reliably provide the freedom from insect infestation demanded by many markets; and they are relatively inexpensive to apply. Despite their central importance, however, there are a surprisingly small number of chemicals used in the protection of stored products. Chemical residue levels are tightly regulated as stored products are usually foods. In addition, because of the often large volumes of commodity involved and convenience of application, fumigants are frequently the preferred treatments, rather than liquid insecticides. However, fumigant use requires strict workplace health and safety precautions and must comply with stringent environmental constraints. These factors, coupled with toxicological considerations, limit the range of materials available for application to grain and make them costly to develop. For these reasons, loss of any one chemical treatment will have a significant impact on pest management. Consequently, the development of resistance in stored product pests to any registered insecticide is a particularly significant problem that requires urgent solutions

Potential of Tyrophagus putrescentiae (Schrank) (Astigmata: Acaridae) for the Biological Control of Lasioderma serricorne (F.) (Coleoptera: Anobiidae)

This work investigated the potential of Tyrophagus putrescentiae (Schrank) (Astigmata: Acaridae) to control Lasioderma serricorne (F.) (Coleoptera: Anobiidae) in the laboratory. L. serricorne is the most destructive insect pest ever found on stored tobacco. The experimental delineation had 33 arenas being each experimental unit with 11 arenas of experiments with eggs, larva of L. serricorne with the density of T. putrescentiae maintained constant, where from 11 of these arenas, eight were for the analysis of predation and three to evaluate the natural mortality of the insect. The highest predation rate was found during the larval stage with, approximately, 54, 68 and 78% mortality of L. serricorne from the fourth until the sixty day of predation. These results indicated that it was possible to use the predatory mite T. putrescentiae in pest management programs of L. serricorne in the storage units of tobacco