Samples of a dipteran pest of wheat were tested to confirm identity, describe local populations and suggest the use of deploying resistance (R) genes in wheat cultivars for control of Mayetiola destructor, Hessian fly (HF). Morphological evaluation of adults and a free-choice oviposition preference test documenting that females overwhelmingly preferred to oviposit on wheat instead of barley supported they were HF. Using the cytochrome c oxidase subunit I (coxI), the Barcoding Region, nine haplotypes were revealed. Two were found only in the Israeli collections and averaged 3% sequence divergence compared to the other seven haplotypes found in the United States, Israel and Syria. In evaluations of virulence, the Israeli HF in culture was virulent to 11 of the 19 (R) genes tested, and complementation analysis documented that, for four of the R genes tested, the Israeli HF shared loci for virulence with HF from the United States. Levels of HF infestation at seven Israeli fields were at least at the 5–8% level, which historically has indicated a significant yield loss. Microsatellite genotyping of the five HF collections from Israel revealed mixed populations in Israel that are distinctly separate from the single population in Syria.

The most widely used and successful cultural practices for managing plantparasitic nematodes are resistant cultivars and some elements of cropping systems, such as rotation crops, cover crops, or nematode-antagonistic crops. Exclusion and sanitation practices, such as use of nematode-free planting material, site selection, and weed management, are useful in limiting infestations. Soil solarization, organic amendments, biological control, fallow, flooding, timing of planting dates, or tillage practices may be helpful in some areas, but additional research is needed to optimize their use. Most management methods emphasize reduction of nematode populations, but improvement of crop tolerance to nematodes should not be overlooked. For their successful use, most of these alternative methods require detailed knowledge of nematode and plant biology and ecology, and it may be necessary to integrate several practices for maximum nematode suppression. Although the basic principles of nematode management are generally known, detailed data often are lacking on specific combinations of nematodes and host crop cultivars. Consequently, the availability of such data will likely determine whether nematodes can be managed successfully in a particular situation.

Sorghum is one of the most important cereal crops in West Africa, and the head bug, Eurystylus immaculatus Odh. (Hemiptera: Miridae) is the key pest of grain sorghum in this region. A range of sorghum genotypes were evaluated for resistance to sorghum head bug at Sotuba (Mali) and Kamboinse (Burkina Faso). Genotypes CSM 388, IS 14332, Malisor 84–7, Sakoika, S 29 and Kamboinse local were resistant to head bugs, both under natural and headcage screening. Head bug resistant genotypes had a lower percentage of head bug damaged grain. The food quality of head bug damaged grain was very poor and unacceptable.

Cultivar non-preference was identified as a component of resistance to head bugs, and CSM 388 was nonpreferred compared to E 35–1. Panicle compactness was positively associated with head bug numbers and grain damage. However, genotypes with loose panicles were also susceptible to bugs. Long glumes (>5 mm), days to glume opening (>20 days after anthesis), >50% covering of the grain by the glumes, and grain hardness contribute towards resistance to Eurystylus immaculatus. This information will be useful for developing a programme to breed for resistance to this insect in West Africa.

Leaf extractables/fractions obtained from the leaves of soybean PI 227687 showed greater antifeedant activity towards the third-instar larvae of the cabbage looper, Trichoplusia ni (Hub.). Extraction of leaves with ethyl acetate followed by 60% methanol, and counter-current partitioning of leaf extractables between ethyl acetate, water and hexane was not convenient for isolation of antifeedants. Methanol (60%) in water extracted most of the antifeedants from leaves, and this extract when partitioned between ethyl acetate and water (the latter repeatedly extracted with the former), concentrated the antifeedants from soybean leaves for further processing on thin layer chromatography or high performance liquid chromatography.

There were quantitative differences in ethyl acetate fraction of PI 227687 (6%) and Davis (3.2%), and in flavonoids resolved at Rf 0.10–0.20 in benzene: ethyl acetate: methanol (4:3:3). Most of the flavonoids with antifeedant activity resolved at Rf 0.10–0.80. The antifeedant activity of flavonoid bands from PI 227687 was greater than the corresponding bands of Davis.

Sorghum head bug, Calocoris angustatus Leth. (Hemiptera: Miridae) is an important insect pest of sorghum in the semi-arid tropics. A technique to screen for resistance to head bugs under field conditions was tested. Planting infester rows of susceptible cultivars (CSH 1 or CSH 5), 20 days before the test material or planting early (40–45 days) flowering lines (IS 802, IS 13429 and IS 24439) along with the test material, split planting of test material at 15-day intervals, grouping test material according to maturity, and use of sprinkler irrigation to maintain high humidity, were found effective in increasing the efficiency of screening and selecting for resistance to head bugs.

A headcage technique to screen for resistance under no-choice conditions has also been developed. Panicles infested with 10 pairs of bugs at pre- and half-anthesis, result in maximum population build-up and grain damage under headcage. This technique is useful for confirming the resistance observed under field conditions.

Under natural infestation, five genotypes harboured relatively lower head bug numbers than the susceptible checks, but only three (IS 17610, IS 17618 and IS 17645) maintained their level of resistance under the headcage. Seed germination was > 70% in these genotypes compared to < 10% in CSH 1 and CSH 5.

The distribution and existing control measures for three important Chilo spp. (C. partellus, C. orichalcocilliellus and C. sacchariphagus) to cereal crop production in 10 east African countries and their neighbouring Indian Ocean Islands are reviewed. Various cultural, biological, host-plant resistance/tolerance and chemical control methods developed in the past 30 years of cereal research programmes are discussed. Cultural methods are very effective on Chilo spp. control, but are not widely practised. Although several effective natural enemies have been identified for Chilo spp., very few systematic programmes of their utilization have been effected. Several resistant/tolerant maize and sorghum lines have been reported, but they are not yet fully used. Chemical control though effective, has proved rather unsuccessful in traditional agriculture. Suggestions to incorporate these control methods in Integrated Pest Management (IPM) programmes for Chilo spp. in different places in the region are given.

Chilo species are the most important stem borers of sugar-cane. They cause heavy losses to sugar-cane crop and continue to suppress yield in the sugar industry. The control of these borer species through insecticides has been difficult as the damaging larvae spend most of their life-cycle within the cane plant. The breeding of borer resistant varieties is an ideal approach for controlling the damage as it does not cost the grower anything extra, is effective at all levels of pest infestation and its effects are cumulative and long lasting in reducing the pest population. Many plant characters such as leaf surface, rind hardness, leaf sheath tightness, fibre content, stalk pith and diameter and plant vigour have been associated with borer resistance. In sugar-cane breeding, the inclusion of borer resistance characters, in addition to many other agronomic characters required of a commercial variety, is rather difficult due to the segregating nature of this plant. Therefore, it is better to use, as parent varieties the few varieties showing marked resistance without knowing the actual reasons of resistance. The joint efforts of sugar-cane breeders and entomologists in production and selection of a large number of seedlings for desired characters can help to solve this problem to a greater extent.

The paper stresses the fact that an integrated pest management system is not a new concept leading to a more stable agroecosystem, but was practiced by the farmers for centuries; host-plant resistance is one of its major components. The system was destabilized by the introduction of new sorghum varieties and hybrids not resistant against the major sorghum insect pests like shootfly Atherigona soccata (Rondani); stem borer, Chilo partellus (Swinhoe); midge, Contarinia sorghicola (Coquillet); and headbugs, Calocoris angustatus (Lethiery). In order to balance the agroecosystem again, an integrated insect pest management system for sorghum has to be developed based on traditional pest management practices. These are host-plant resistance, cultural control and biological control. Insecticides should be used only if absolutely necessary. For a better understanding of such a control approach, a summary of the biology and population dynamics of the major insects is given, together with a brief account on the levels and mechanisms of host-plant resistance so far known. Based on this information, the rainfall pattern, plant duration to maturity, time of planting, natural enemies and insecticides, a sorghum based integrated pest management system is proposed for the monsoon and post-monsoon season in which host-plant resistance alone or in combination with the above mentioned control methods could be used.