A study of the resting site preferences of Glossina palpalis gambiensis in an area of a gallery forest in the Northern Guinea Savanna of Mali, infested exclusively by G. p. gambiensis was conducted in February, 1980 (hot dry season). Five site-types were compared: fallen logs, boles, undergrowth, tree canopies and branches. Distribution of resting flies was as follows: fallen logs (55.62%), boles (35.24%), undergrowth (8.4%), tree canopies (0.61%) and branches (0.00%). Most of the flies were collected during the periods 06.00–09.00 (37.47%) and 09.00–12.00 hr (46.5%). On boles, 86.06% of flies were found below 1.0 m and no flies were collected above 2.0 m. These results are compared to those obtained during simultaneous studies on the resting site preferences of G. p. gambiensis in an area along the same gallery forest, with mixed G. p. gambiensis and G. morsitans submorsitans infestation. Possible reasons for the differences observed are discussed.

The sternal gland in Macrotermes michaelseni is located in the anterior half of the fifth abdominal sternite between the third and fourth abdominal ganglia and overlapped by the fourth sternite. It is found in all castes including newly-swarmed de-alates. The gland is largest in major workers followed by major soldiers, minor soldiers and minor workers and is the only source of trail pheromone. Major workers have the highest potential trail pheromone activity followed by minor workers, male and female de-alates, minor soldiers and major soldiers.

There is a change in trail laying behavior with time and direction of travel, from the culture or from the arena and it can be correlated with the deposition of a light or heavy trail, or no trail at all.

The trail of one major worker leaving the culture is attractive to a significant number of workers for 1 hr 30 min and that of five major workers for 1 hr 45 min. The trail of workers leaving the arena is not as strong, one worker trail is attractive for 1 hr and five worker trails for 1 hr 15 min. The well-established trail is attractive to a significant number of workers for 9 hr. All trails lose attractiveness at a constant rate.

Three consecutive generations of Hypsipyla robusta Moore (Lepidoptera: Pyralidae) were reared on the McMorran–Grisdale Diet (MGD) medium. Mortality rates among the older larvae were consistently low (less than 1.0%) but high (up to 50%) in the first instar stage which was due primarily to escapism and non-feeding. Developmental period from egg to adult was not adversely affected by the artificial diet and ranged between 29 and 41 days. However, a comparison of numbers of larval instars and pupal sizes indicated that the nutritional quality of the MGD and natural food sources differed appreciably. A longterm study to evaluate the usefulness of the MGD for planned mass rearing programmes of H. robusta is recommended.

Temperature-time and temperature–velocity equations are given for egg, larval and pupal stages of the sorghum shootfly, Atherigona soccata. Preimaginal development (from egg deposition to adult emergence) on sorghum CSH-1 seedlings lasted 19.5, 26.3, 33.8 and 76.8 days at 30, 25, 20 and 15°C, respectively. The sorghum shootfly showed optimal development and survival at 30°C. Lower threshold temperatures were 13.8, 10.2 and 11.8°C for the egg, larva and pupa, respectively. Host plant condition affected larval development and survival; pupal weight was higher and larval mortality lower in insects reared on fertilized and normally watered seedlings than on unfertilized and water stressed seedlings.

The leafminer, Liriomyza trifolii Burgess, a polyphagous agricultural pest, can attack crops at different stages of development; some are attacked at the beginning of the crop cycle and others at the end of the cycle. Experiments on the differential susceptibility of the bean Phaseolus vulgaris and the potato Solanum tuberosum plants were done to get some information about factors which influence host selection by the leafminer. The distribution and density of leaf trichomes, as well as the nutritional status of the host plants, were found to be important in host selection. High trichome density acts as a physical deterrent to Liriomyza flies, just as senescing primary bean leaves induce non-acceptability. When given a choice, flies prefer bean to potato leaf discs, though the latter possess less trichomes. Other factors (chemical attractants and some nutrient components) might therefore also be involved in the complex host selection behaviour of L. trifolii.

In a recent review of host location by tsetse an attempt was made, using previously published data, to draw some general conclusions regarding the range of detection of warm-blooded hosts by tsetse and mosquitoes. The paper included some misleading and invalid conclusions. This topic and the supporting data are reconsidered. It is suggested that the maximum range of a positive response by mosquitoes or tsetse to stationary cattle baits may be expressed as 0.31 × host weight (kg)0.90 (P < 0.001).

The mating behaviour, with emphasis on the sexual maturation, of male tsetse, Glossina morsitans centralis (Machado, 1970) reared at the Uganda Trypanosomiasis Research Organization (UTRO) was investigated. Mating behaviour of 2–15 day-old males and 3-day-old females was observed. Three mating phases were recognized as courtship, mounting and genital interlocking (coupling), and jerking in most male flies tested.

The efficiency in coupling increased with age. Most males mounted the female mates after one attempt. The mating period in most males tested was between 1 and 3 hr, while the jerking period was on average 2.5 min. Most of the matings resulting in insemination lasted longer than 1 hr in all the age groups tested. The ability to inseminate and the degree of insemination produced by the older male flies were better than those by the younger ones. These results are discussed in relation to laboratory rearing of Glossina.

Incidence and extent of damage resulting from attack by the striped bean weevil Alcidodes leucogrammus Erichs, were assessed by random sampling of cowpea plants in monocropped and within maize-cowpea-sorghum intercropping combinations at two locations. The biology and damage symptoms caused by the bean weevil are discussed. The effect of A. leucogrammus incidence on cowpea nodulation is evaluated and evidence presented that the weevil attack causes a reduction in the number of nodules. Emma 60, a local cowpea cultivar, exhibits some degree of resistance against A. leucogrammus (P < 0.05). Sorghum–cowpea intercropping combinations have significantly fewer weevils (P < 0.05) possibly as a result of the close spacing and tillering capacity of the sorghum companion crop which prevents or obstructs the weevil migration between rows.

The composition and preparation of a general purpose artificial diet for rearing insects is described. Forty-one species were reared for one generation or more, and 56 species were partially reared or maintained on this diet. The advantages and applications of using a single diet for multiple-species rearing are described.

The diet is economical (NZ $2.37 per kg) for general laboratory rearing. In freeze-dried form it can be used for bioassays of pathogens, pesticides, insect growth regulators, plant resistant chemicals and other toxins, and has a potential market in the development of insect rearing kitsets for educational purposes.

The susceptibility of 23 cotton genotypes to spotted bollworm, Earias vittella, was studied under natural infestation during 1977 and 1978 rainy season at Delhi, India. There were substantial differences in bollworm damage and larval population in different genotypes. Damage in shed squares and bolls was higher than in green bolls picked up from the plant. The damage/larval population in the less susceptible cultivars (Hindiweed, XG-15, HR-26 # 8XH · HG-6-IN and Sanguineum) was lower than in the susceptible check (BJR) and the trial mean. The differences in susceptibility were more pronounced at the moderate damage levels and that the damage in less susceptible cultivars increased or decreased according to the insect pressure.

There were significant differences in the gossypol, tannins, moisture, phenols and sugar content among the genotypes tested. Gossypol, tannins and moisture content of bolls and squares were negatively correlated with bollworm damage and larval population. Free phenols showed negative, but lower correlation coefficients with bollworm damage. Sugars contributed towards susceptibility while nitrogen content of bolls did not show any effect on bollworm damage. The less susceptible cultivars had higher amounts of gossypol and tannins. Some genotypes showed ovipositional non-preference because of smooth leaves.

Many factors appeared to influence the genotypie susceptibility to spotted bollworm, of which gossypol, tannins and ovipositional non-preference (due to smooth leaves) were the major factors. Gossypol and smoothness are genetically inherited and can be manipulated through crop improvement. The rating of the number and size of pigment glands on the calyx tubes and hairiness on the under surface of leaves can be used as important marker characters in breeding for spotted bollworm resistance.

The oviposition behaviour of spotted bollworm, Earias vittella Fab. was studied on 23 cotton genotypes under field and laboratory conditions. There were substantial differences in the number of eggs laid on different genotypes. More eggs were deposited on the bolls compared to leaves and squares. The relative oviposition preference differed under the field and laboratory conditions in the case of some genotypes. Leaf hairiness was significantly and positively correlated with number of eggs laid both under field and laboratory conditions. The effect of oviposition on varietal susceptibility appeared to be modified through other factors, such as gossypol and tannins. However, oviposition non-preference was one of the important resistance mechanisms in some cotton genotypes.

A number of butadienes and their thiophene congeners were found to be phototoxic toward the larvae of the mosquito Aedes aegypti and of the fruit fly Drosophila melanogaster. Only the first instar larvae of the fruit fly were killed by the chemical treatment in the presence of long wavelength ultraviolet light (UVA), while the mosquito larvae were all affected by a similar treatment which was performed with either UVA or natural daylight. With one exception, the mosquito larvae were all killed within 1 hr of daylight exposure in the presence of an average concentration of 0.8 ppm of the phototoxin. The fruit fly larvae were killed within 20 min of exposure to UVA when in contact with a filter paper disc containing 1.13 × 10−5 g/cm2 of the phototoxin.

An extensive survey for natural pathogens and parasites of mosquitoes as prospective biological control agents was carried out in Israel. Coelomomyces (Class, Chytridiomycetes; Order, Blastocladiales), a fungal genus of which all but a few members are specific to mosquitoes, was not known to be present in Israeli waters. Therefore, mosquito and copepod host-range tests were conducted with Coelomomyces psorophorae obtained from abroad, in order to test the desirability of introducing Coelomomyces as a contribution to mosquito control. Acanthocyclops viridis, a cosmopolitan copepod relatively common in Israel, was duly infected with Coelomomyces psorophorae. However, the infectivity of Israel's most common pest mosquitoes (Culex pipiens complex) proved low.

Field plots and cage experiments were conducted to study the effects of intercropping sorghum, millet and maize on infestation by the most important lepidopterous stem-borers of the three crops. Intercropping was done both within and between rows. The highest number of B. fusca eggs were deposited on sorghum, followed by maize and least on millet, among the sole crops. The number of eggs found in the crop mixtures was intermediate between the numbers obtained when the crop components comprising the mixtures were considered as sole crops and averaged. The inability of B. fusca adults to effectively utilize millet for oviposition, reduced larval infestation of sorghum stems when interplanted with millet. The best combination was millet interplanted with sorghum in alternate stands within the same row. The millet stem-borer, A. ignefusalis also showed definite preference for millet, but infestation on millet did not seem to be affected by intercropping with either sorghum or maize.

Three 9-acridone alkaloids, melicopicine, tecleanthine and 6-methoxy tecleanthine were isolated from the bark of Teclea trichocarpa. Melicopicine and tecleanthine exhibited mild antifeedant activity against the African armyworm, Spodoptera exempta. All the three alkaloids showed antimicrobial activity against the fungus, Cladosporium cucumerinum and the bacterium, Bacillus subtilis.

Parasitization of P. brassicae L. by A. glomeratus L. was found to be between 63.79 and 76.52% in Farm 1 and 92.68 and 93.43% in Farm 2. Population density of the parasitoids ranged between 35.16 ± 6.05 and 57.76 ± 13.20. The developmental period of the parasitoids within the host was 21 days and the pupal period 9 to 10 days. The population of the parasitoid showed a steady increase during November–December. The rate of pupation of P. brassicae showed a decline from 36.21% in mid-November to 23.48% in later November in Farm 1 with an early crop. In Farm 2 with a late crop the pupation rate dwindled from an already low 7.32 to 6.57% by late December.

Studies on the relative abundance of pod-borers and distribution patterns of the dominant borer, Adisura atkinsoni Moore, were conducted at Bangalore (Karnataka, India) with a view to develop a field screening procedure in the field bean, Lablab niger, to pod-borers. Nine species of borers constituted the borer complex on L. niger. The borers population peaked in October.

Eggs and early instar larvae of Adisura followed a clumped distribution pattern. Older larvae, however, were distributed uniformly in the field. Adisura moths preferred to lay eggs between 50.8 and 63.5 cm on the erect type of L. niger and between 101.6 and 114.3 cm on the creeping type of the plant. Plant height had a significant positive correlation with the maximum number of Adisura eggs, but up to nearly 115 cm. Adisura eggs peaked in number during October, while larvae did so during November–December. Implications of the aforementioned observations in field screening are suggested.

Seventy cultivare of sorghum representing recently released varieties, hybrids, experimental varieties, lines bred for stalk-borer resistance and local resistant stocks were tested for stalk-borer resistance under artificial infestation during monsoon (July–October) season. There were significant differences among varieties for leaf-feeding injury, per cent ‘dead hearts’, number of holes and tunnels and per cent tunnelling. Released hybrids and local varieties were susceptible for different parameters. Thirteen varieties viz., SPV Nos. 35, 103, 107, 110, 135, 140, 192, 229, E 302, E 304, P 37, R 133 and CSV-8R were at par with resistant varieties for per cent tunnelling per plant. Long peduncle varieties were relatively susceptible.

Leaf-feeding injury, per cent ‘dead hearts’ and tunnelling parameters were not significantly correlated and independent of each and none of them could be related to grain yield. Number of holes, number of tunnels and per cent tunnelling were positively correlated. Thus, number of holes per plant or internode may be a good indicator of per cent tunnelling and can conveniently be used as a criterion for evaluating germplasm to stalk-borer (Chilo partellus Swin.) resistance. The varieties CSV-8R, SPV-35, SPV-103, SPV-140 and SPV-192 were identified as promising sources of resistance to stalk-borer.

The insect growth regulator, 6′,7′-epoxy-3′-ethyl-7′-methyl-dec-2′-enyl 6-ethyl-3-pyridyl ether, at 10 ppm applied to rearing media, did not prevent oviposition or hatchability of the eggs of Tribolium confusum. The insect growth regulator (IGR) apparently had no effects on the development of younger larvae, and no morphological abnormalities were observed in these instars. However, the IGR prevented metamorphosis of the last larval instar. These larvae continued to moult several times, became larger than larvae in untreated food, but failed to pupate; as a result, no adults emerged from the treatments.