The use of fish meal and detergent water has been shown to be simple, economic and reliable for sampling of shootfly populations. Various mixtures of fish meal with other ingredients were evaluated. The most potent mixture was fish meal-yeast-ammonium sulphide, but generally fish meal alone was adequate and the most readily available attractant. The attractance of fish meal was found to be related to its degradation; it increased from the first to the third or fourth day, and then decreased. The chemicals responsible for the attractance of fish meal have yet to be identified, but in all probability they may be the amines resulting from biodegradation of the meal.

This paper includes a description of the internal reproductive system of the female sorghum shootfly, Atherigona saccata, as well as studies on egg maturation and survival, and effects of mating and/or presence of the male on egg maturation, fecundity and fertility. The number of ovarioles per female ranged from 20 to 47. A. seccata exhibits autogeny, but carbohydrate is essential for egg production and survival. Nutritional deficiency led to a high incidence of oocyte resorption. A mixture of baker's yeast and sugar was a better adult food than brewer's yeast and glucose. Sorghum (cereal) aphid honeydew was a nutritious adult food. Shootflies provided with sorghum aphid honeydew showed an acceleration of vitellogenesis, a decrease in the frequency of oocyte resorption and a shortening of the preoviposition period. Egg maturation does not seem to be influenced directly by mating or by the presence of males. The continuous presence of the male also has no significant effect on fecundity. Shootfly females seem to mate only once and this single mating ensures fertilization of eggs laid even long after mating.

Sorghum (Sorghum bicolor) is an important food crop, especially of the semi-arid areas of Asia and Africa. One of the major constraints affecting the popularity of high-yielding hybrids and varieties is their extremely high susceptibility to insect pests.

Painter (1951) has reviewed in detail the work done on resistance in sorghum to the chinch bug (Blissus leucopterus), corn leaf aphid (Aphis maidis) and sorghum midge (Contarinia sorghicola). In the last decade and a half considerable work has been done on resistance to the shootfly (Atherigona seccata), stem borer (Chilo partellus) and sorghum midge (Contarinia sorghicola). By conducting multilo-cation screenings of world germplasm under natural and artificial infestation conditions, not only have promising sources of resistance been identified but a number of them have been utilised in crossing programmes to develop high-yielding resistant cultivars. Some sources with multiple resistance have also been identified.

The mechanisms of resistance in sorghum to the major pests have been investigated. It is seen that the mechanisms are generally complex and the observed field resistance is the total reaction of several components. There are several leads available which justify further intensive work, especially on identifying naturally occurring plant products associated with antibiosis mechanism.

From field screening of two international nurseries of the sorghum shootfly (Atheriaona saccata), seven promising cultivars were selected for investigating the mechanism(s) of resistance. These cultivars were IS 1054, IS 1082, IS 2146, IS 2195, IS 2312, IS 3962 and IS 5613. CSH-1, a hybrid variety from India, was used as a susceptible control. Results from observations on larval development and mortality and the longevity and fecundity of resulting females when released on either CSH-1 or the parent cultivars are reported.

Mortality among the first-instar larvae was very high on IS 2146 followed by IS 2312 and IS 5613. IS 2146, IS 3962 and IS 2312 sustained the least growth of larvae. The larvae in these cultivars were often confined to the upper region of the central shoot.

The survival rate of flies from IS 2146 was very low, and the longevity was significantly reduced in the case of flies from IS 2146 and IS 2195. The preoviposition period was significantly longer when flies were released on IS 1082 and IS 2312. Fecundity of the flies did not differ significantly when released on CSH-1; however, it was significantly reduced when released on parent cultivars in all cases except IS 1054. It is concluded that IS 2146 possesses strong antibiosis for the sorghum shootfly followed by IS 2312 and IS 5613.

The behaviour of shootfly resistance is examined over the Fl, F2, F3 and advanced generations. The Fl is almost intermediate between two parents with an added heterotic advantage of a lower ‘dead-heart’ percentage. Resistance shows partial dominance under low to moderate shootfly infestation but this relationship may shift under heavy infestation conditions.

The resistance is polygenic in nature and governed by additive genes. In the absence of host immunity, gradual accumulation of favourable genes is possible by line breeding from R × I and I × I crosses by selecting 1 SD below the population mean. Selection for multiple characters limits the genetic advance for shootfly resistance—resulting in 0- 5% selection intensity and relatively less resistant but high yielding desirable progenies. Multilocation tests enable the selection of varieties stable for shootfly resistance.

The biology of the sorghum shootfly, Atherigona soccata Rondani, was studied at the Corn and Sorghum Research Centre, Thailand. The preoviposition period is 3–5 days long. The females deposited a mean of 238 eggs with an average incubation period of 3 days. The larval development required an average of 7.8 days, and the pupal stage was 7.1 days long. The adults were reared with ordinary sugar, yeast and water. The females lived an average of 30 days and the males 20 days.

Carbofuran granular formulation is still the leading product for the control of the shootfly at the Research Centre. The application rate in the seed furrow is 0.45–0.60 kg a.i./ha with a row spacing of 75 cm. Furadan® 30ST, an emulsifiable formation of carbofuran, can also be used as a seed dressing at a rate of 20 cm3/kg of seeds. Counter®, another soil systematic insecticide, has been found effective in controlling the sorghum shootfly.

A modification of the ICRISAT trap for the sorghum shootfly is described. The trap may be effective in reducing the fly population.

The introduction of high yielding sorghum hybrids in the mid-1960s indicated that the new cultivars were highly susceptible to insect pest attack. Use of chemicals for the control of the snootily, Atherigona soccata (Rondani), became necessary to realise a full yield potential.

This paper briefly reviews the earlier work on conventional foliar sprayings and dustings of the available insecticides which generally failed to give an effective control of the shootfly.

Work carried out in the early 1960s showed that the application of phorate, disulfoton, aldicarb and carbofuran granules in the soil at the time of sowing was very effective in controlling the pest. Recently two more insecticides, viz. isofenphos and fensulfothion have been found to be equally effective. However, the cost of applying these insecticides is rather high.

Seed treatment with carbofuran at 5 parts a.i. per 100 parts of seed proved to be highly effective and economical. It is now being widely used by farmers in the major sorghum growing area of the country. It has been found that dosage of carbofuran can be further reduced by using a 6:4 mixture of treated and untreated seed.

Trials have been conducted to determine the residues of effective insecticides in the soil and in plants at different intervals. Investigations have also been carried out to establish the correlation between the residues of different insecticides in plants and their efficacy in controlling the shootfly. A future strategy for the chemical control of the shootfly is outlined.

An integrated approach to the management of the sorghum shootfly (to keep its population below economic injury level) has been a major thrust of sorghum research workers during the last one and a half decades. The necessary foundation has been laid by detailed studies on the biology of the pest and a fairly thorough understanding of the effect of different ecological factors on the shootfly population. Based on seasonal incidence studies, sowing immediately after the onset of monsoon has proved to be effective for avoiding shootfly damage.

A large number of high yielding and shootfly-resistant derivatives have been developed by crossing agronomically desirable exotic lines with identified resistant sources. The new hybrids and varieties released recently possess low to moderate levels of resistance.

Parasites and predators affecting different stages of the shootfly have been identified but utilization of these natural enemies for the biological control of the pest is yet to be undertaken.

Carbofuran seed treatment has proved to be highly effective for protecting sorghum from shootfly damage. Some other insecticides have also been found to be promising.

Based on the control methods available at present, an integrated package has been recommended for implementation in traditional sorghum growing areas of the country.