Controlling Insect Pests of Stored Products Using Insect Growth Regulators and Insecticides of Microbial Origin (NRI, 1994, 58 p.) Section 5: Overall summary Insect growth regulators Microbial control agents Recommendations Conclusion

Controlling Insect Pests of Stored Products Using Insect Growth Regulators and Insecticides of Microbial Origin (NRI, 1994, 58 p.)

Section 5: Overall summary

Insect growth regulators

A wide range of IGRs have been produced, many of which are currently at various stages of development. The agrochemical manufacturers of these compounds are seeking to register them in individual countries for use against specific insect pests of agricultural or horticultural importance. With the exception of methoprene, manufacturers do not, however, appear to be considering IGRs as potential grain protectants at the present time.

In this review, collation of current information on the IGRs which have been tested against insect pests of stored products has been attempted. Only the JHA methoprene has been commercially registered and accepted as a protectant for durable stored products. Its potential is limited by the need for an integrated pest management approach to enable the effective control of the more tolerant insects such as Sitophilus spp.

It has been suggested by Bengston (1987) that the speed at which IGRs will be introduced will depend largely on the following three factors: the speed of development of resistance to conventional pesticides; the acceptability of their residues; and the competitiveness of IGR prices. Another factor is the need to encourage the agrochemical industry to put forward candidate IGRs for consideration as grain protectants.

Microbial control agents

The use of microbial agents for the control of insect pests of stored products is still in its infancy and further research needs to be undertaken.

As with IGRs and chemical insecticides, the market potential for protectants of durable foodstuffs is limited, and this, in turn, limits the number of companies researching into microbial control. In spite of the costs, and the risks and time involved in screening, a few companies have succeeded in producing useful products. Frequently, progress has only been achieved when governments have supported research projects concerned with the control of agricultural or forestry pests.

Recommendations

Of the compounds reviewed, the following warrant further consideration as potential protectants of durable foodstuffs and stored products:

· methoprene
· fenoxycarb
· diflubenzuron
· triflumuron
· teflubenzuron
· hexaflumuron chlorfluazuron
· flufenoxuron
· baculoviruses
· Bacillus thuringiensis
· protozoa
· fungi

Conclusion

Only a few of the alternative materials examined in this review have reached the stage where they could be used commercially in the grain storage market. Most of the IGRs are still being tested in the laboratory or in small-scale field trials. Considerable research is needed to isolate and identify potential viral, protozoan, and fungal agents for the protection of stored food against a wide range of pests. Owing to their generally species-specific nature, microbial agents will have to be integrated with other control measures. Methods for the successful integration of promising agents with other control measures will therefore need to be explored.

There is, however, undeniable scope for using IGRs and microbial agents to control insect pests at both small farm and large central storage levels, particularly as the number of registered conventional insecticides is reduced. There may also be many economic, social and political benefits to be gained from using alternative materials.