Desmodium tortuosum (Sw) DC (Papilionaceae) is a preferred wild host of Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) which is an important pest of cotton in Tolima, Colombia. From November 1976 until March 1979, cotton and D. tortuosum were compared and contrasted in the field as hosts of the pest. A very high infestation level of H. virescens in cotton in 1977 was preceded by an extremely low infestation level of the insect in D. tortuosum previous to the cotton-growing season. In 1978 and 1979 moderate infestation levels in cotton were preceded by moderately low infestation levels of H. virescens in D. tortuosum previous to the cotton growing season in both years.

Progressively less eggs were laid on cotton versus D. tortuosum as the cotton plants aged. Peak numbers of H. virescens occurred during the latter part of the cropping season and immediately after. A mean of 13% of first-instar larvae of H. virescens on D. tortuosum were found stuck by the glandular trichomes of the plant. On cotton significantly more eggs were found during the week of full moon than new moon or first quarter. Apparent sterility and pre-hatch mortality of eggs of H. virescens varied between 1–5 and 0 and 7%, respectively, for both hosts combined.

Egg parasitism by Trichogramma sp. (Hymenoptera: Trichogrammatidae) in cotton was 1.5% in 1977, presumably due to excess use of pesticides, and 23.5% in 1978 when pesticides were not used much. Parasitism of eggs on D. tortuosum by the same parasite averaged 1%; the glandular trichomes of D. tortuosum trapped and killed adult Trichogramma.

The fact that infestation levels of H. virescens in cotton were very high in the year that they were very low in D. tortuosum previous to the cotton-growing season, and moderate in cotton during 2 years that they were not as low previously in D. tortuosum suggests that the continued presence of the pest many aid its natural regulation, perhaps by providing a source of hosts to H. virescens specific parasites.

If relative levels of oviposition in cotton could be predicted by lunar cycles this would aid in planning control strategies, such as massive liberations of egg parasites and more intensive monitoring of infestation levels during predicted peak periods.

Effects of temperature on female longevity, fecundity and fertility of the sorghum shootfly, Atherigona seccata Rondani, were investigated. The longevity, preoviposition and oviposition periods, eggs per female per day, mean eggs per female and fertility (per cent eggs hatched), for the shootflies maintained at constant temperatures of 20, 25 and 30°C and alternating temperatures of 30°C (photophase) and 20°C (scotophase) referred to as 20–30°C were determined. At lower temperature (20°C), the longevity, preoviposition and oviposition periods were prolonged considerably, while daily egg production, mean fecundity and fertility were decreased. Higher temperature (30°C) had the reverse effect on preoviposition and oviposition periods as well as daily egg production. There was a significant positive correlation between the pupal weight and the number of eggs laid by the fly at 20°C. Egg mortality increased with advance in maternal age. The rate of increase in egg mortality was faster at 30°C than at lower temperatures.

Results of 7 years' experiments conducted in South China indicated that root-zone application of systemic insecticides effectively controlled nearly all the potential insect pests of rice—the yellow stem-borer, the striped stem-borer, the pink borer, the rice leaf folder, the rice gall midge, the brown planthopper, the greem leafhopper, the rice thrip and the rice weevil. Altogether, 16 compounds have been evaluated for the control of various species. Applications of carbofuran mixed with derivatives of nereistoxin (padan, thiocyclam or dimehypo) in the root-zone were found to be most effective against the major insect pests. The merits and demerits of root-zone applications has been discussed in this paper.

The termite Macrotermes michaelseni (Sjöstedt) builds conical earth mounds with no external openings. The structure of the nests is described. The fungus combs and the nursery are in separate parts of a single hive chamber, and thus occupy the same air space. A closed system of inter-connected passages in the mound facilitates loss of metabolic heat to the atmosphere.

The differential attraction by 2 pigeonpea cultivars has been tested through the oviposition behaviour of Heliothis armigera females in a standardized laboratory assay. Seedlings of a susceptible variety (PPE-50) are under choice conditions significantly more attractive at a distance, and without contact allowed other than those of the resistant variety (PPE-45). The volatile signal is contained in the hexane extract from PPE-50 leaves, as shown in the oviposition assay, and after vacuum distillation is present in the more volatile fractions of the mono- and sesquiterpenoids. These compounds, which are also contained in the hexane extracts of 2 more pigeonpea cultivars, a check of medium susceptibility (T-21) and a wild relative (Atylosia scarabaeoides), were compared by capillary gas chromatography. The 4 pigeonpea varieties were characterized by their specific aromagrams, a method which may also advantageously be used in pigeonpea breeding programs.

Eggs and larvae of the bollworms Earias spp. followed a uniform distribution on G 27, LD 133, LD 230 (Arboreum) and F 414 (hirsutum) cotton varieties in Ludhiana (Punjab). Clump distribution of Earias eggs and larvae on the four cotton varieties may result from environmental heterogeneity. Although Earias gravid females laid maximum eggs at the top (41–50 cm) plant canopy mostly, examination of the whole length of the plants is suggested for sampling Earias on the four varieties.

Sample sizes of 10 plants in arboreum and seven in the hirsutum variety resulted in reliable estimates of population at 5% risk level. Injured fruiting bodies and larval numbers were significantly and positively correlated.

Field investigations were conducted at Mwea-Tebere Agricultural Research Station, situated in Central Province of Kenya, to evaluate the effects of the infestation of cotton by red spider mites, Tetranychus sp., on its growth and yield components. The results obtained revealed that mite damage adversely affected vegetative growth as measured by the amount of leaf and plant dry matter, number of leaves per plant, leaf surface area and mean size of leaves which were reduced by 67.07, 48.46, 68.18 and 60.37% respectively.

In addition to these effects, it was estimated that seed cotton yields could be reduced by 46.93% per plant due to mite injury. Seed development was adversely affected through the reduction of their weight (seed index), oil content and viability by 9.30, 10.07 and 36.67%, respectively. Similarly, mite damage to cotton plants caused the reduction of lint weight (lint index) and lint ginning percentage by 15.42 and 4.5%, respectively.

Some morphological characters of the rice plant were found to be associated with resistance to the African striped borer, Chilo zacconius Bleszynski. A very low, but negative correlation was recorded between percentages of bored stems and plant height. Positive correlations were recorded between percentages of bored stems and stem diameters, stem thickness, length and width of flag leaves and number of tillers per plant. High silica content in rice plants appeared to be a strong factor in resistance to the striped borer. Negative correlations were recorded between percentages of crude silica content of the plants and percentages of bored stems and number of living larvae per plant. Although each of these factors appeared to contribute to borer resistance, none by itself could be said to be the main cause of such resistance, as some varieties did not conform to some of the characters.

Males of the Triatominae, Panstrongylus megistus and Triatoma infestons, show a considerable difference concerning the time necessary for them to acquire the capacity for the first mating. P. megistus copulates from the eighth day of adult life, irrespective of whether or not it has been fed, while T. infestons copulates about 17 days after the imaginai moult and only after a blood-meal. These differences might be due to the secretory activity of T. infestons male accessory glands whose full development is reached only after two saturant blood-meals. If allatectomy is performed in male P. megistus soon after the imaginai moult, accumulation of secretion does not occur in 3 of the 4 accessory glands. Topical application of precocene II (200 μg/insect)a few days before or soon after the imaginai moult in P. megistus, halves the amount of secretion in the accessory glands.

The effect of phenolic compounds on the preference for winter wheat cultivars as hosts by cereal aphids and the effect of the phenolics, reported in the leaves of cereals, on feeding intensity of Rhopalosiphum padi (L.) larvae was investigated. Preference for the studied winter wheat cultivars was associated with the level of phenolic compounds naturally occurring in the plants. The tested dihydroxyphenols showed highest inhibition of the feeding of R. padi larvae.

Reserpine (a pharmacological agent of plant origin) injected into females of Glossina morsitans morsitans was highly effective in preventing ovulation when injected 1–2 days before the egg is normally ovulated. In contrast, reserpine was only modestly effective in blocking parturition, thus suggesting that these two closely related temporal events may be independently regulated. Males injected with reserpine frequently initiated copulation, but sperm and accessory reproductive gland secretions were never transferred to the female. Reserpine, which presumably acts by depleting stores of amines in the nervous system, may have considerable utility in probing the neuroendocrine regulation of tsetse reproduction.

The activity of glutamate-pyruvate transaminase (GPT) increases regularly as the fourth instar larva of Zabrotes subfasciatus develops into prepupa. On the other hand, glutamate-oxaloacetate transaminase (GOT) activity increases significantly (P < 0.05) during the first 12 hr, and then remains at a sufficiently constant level during the subsequent development of this larval instar except at 36 hr of development. However, at the time of prepupation, the GOT and GPT-activities show a decline, which is subsequently followed by an increase during the rest of the prepupal development. The activity of GOT is quite high during the early pupal life, i.e. up to 120 hr. On the other hand, GPT-activity falls significantly (P < 0.05) during the first 24 hr of pupal life and rise up to 120 hr during pupal development. Once again, in the late pupal development, the transaminases remain very active on account of the faster rate of histogenesis. During early adult life, the GOT and GPT are still active, as the early part of adult life of the insect is physiologically quite vigorous and accordingly the energy requirements of the body at this stage are intense. Subsequently, there occurs a regular attenuation of the activities of both of the transaminases in the aging bruchid.

An evaluation of 17 chemicals was conducted in the field at Mwea-Tebere Agricultural Research Station to ascertain their efficacy against the red spider mites Tetranychus sp. attacking cotton in Eastern Kenya. The study became necessary owing to the inadequate control of red spider mites by the recommended acaricide, Dimethoate. Of the chemicals that performed well against the red spider mites, Kelthane, Akar, Morestan and Neoron were considered to be the most suitable replacements for Dimethoate because of their low levels of mammalian oral toxicity. Judged from the overall performance against the red spider mites, these acaricides were also about twice as effective as Dimethoate.

Suitable winter wheat cultivars of different degree of resistance to cereal aphids, Sitobion avenae F. and Rhopalosiphum pali L. have been studied in the field conditions. The differences in the chemical composition of possible attractants and repellants have been analysed. The results confirm the inter-pendence between contents of yellow and orange plant pigments in the leaves of the studied varieties and their preference by the aphids. The leaves of the susceptible cultivars also had the highest level of sucrose. The number of the aphids was directly proportional to the total free amino acids content. The higher degree of resistance of the cultivars was related to the contents free phenols in their tissues and was also associated with a high value of ‘toxicity index’, which is the ratio of free phenols content to free amino acids content. Also the contents of structural polysaccharides (cellulose, hemicelluloses and pectins) of the investigated cultivars were inversely proportional to the degree of their infestation.

The consumption and digestion of two Ghanaian eggplant cultivars (Asesewa and Odwanhwoa) and two exotic cultivars (Black Beauty and Florida Market) by larval Selepa docilis were studied in the laboratory. Daily food consumption was highest on Asesewa and lowest on Florida Market. Total food consumption was significantly highest on Asesewa, followed by Odwanhwoa, Black Beauty and Florida Market. The dry weight of food consumed per unit of larval fresh weight per day was highest on Asesewa, followed by Odwanhwoa, Florida Market and Black Beauty. In general, food consumption was higher on the Ghanaian than on the exotic cultivars. The efficiency of food digestion was significantly higher on the Ghanaian than on the exotic cultivars. Growth of S. docilis larvae, recorded by the daily larval fresh weights, was highest on Asesewa, followed by Odwanhwoa, Black Beauty and Florida Market. The conclusion is made that S. docilis is best adapted to Asesewa, then Odwanhwoa, Black Beauty and Florida Market. Furthermore, S. docilis is better adapted to the Ghanaian than to the exotic cultivars.

Phenology of Arboreum varieties: G 27, LD 133 and LD 230 differed from Hirsutum, F 414 under unsprayed conditions in Ludhiana. Protection to Arboreum varieties at seedling stage against grasshopper and to bolls formed between 1 August to 15 September against bollworm damage was found necessary. In Hirsutum variety, F 414 bolls formed between 16 August to 15 September needed maximum protection from bollworm damage.

At vegetative phase, jassid population was positively correlated with the leaf size and negatively with number of gossypol glands and leaf thickness, and that of whitefly was positively correlated with number of leaves per plant. Six plant morphological characters: number of leaves, squares, bolls, vegetative and reproductive branches and shoot pubescence-affected bollworm infestation significantly and the effect was related to and varied with the age of the plant. Anthocyanin pigment was not detected in any plant part in the four cotton varieties. At vegetative and reproductive phases, gossypol, total phenols, condensed tannins, leuco-anthocyanins and flavenols in leaf, shoot and boll per se did not influence insect pest infestations under field conditions. The parasite population was not related to pest infestations throughout the plant growth. Prédation rates, however, on pest populations seemed to be considerable. Sclereids and lignified cells affected penetration of first instar Earias vittella larvae into bolls.

The individual histories of a herd of up to 671 goats used as hosts for rearing the haematophagous tsetse are summarized in terms of reproductive performance, morbidity and mortality during the period 1976–1978. The data are presented and discussed in relation to the unique management conditions imposed by a fly-rearing programme. The average kidding interval was 11.6 months, with 29.6% twinning. Kids had average birth and weaning weights of 2.3 and 13.6 kg, respectively. The average weaning rate of 40.5% was accompanied by 10.9% cull and 48.6% death losses. The reproductive performance of the East African doe compared well with that of improved breeds, although its lifespan was shorter in confinement. Monthly mortality averaged 2.7% while morbidity averaged 15.9%. The causes of disease are summarized by age groups, and a seasonal pattern of disease incidence was associated with weather extremes and availability and quality of nutriment.

Investigations were conducted in the greenhouse to evaluate the biological performance of Aphis fabae Scopoli when bred on two varieties of the common bean, Phaseolus vulgaris L. Mean developmental period of the aphid was 7.8 days at 26.5°C (range 15.0–32.5°C) on the bean varieties Mwezi Moja (GLP.10) and Red Haricot (GLP.3). The reproductive life of the aphid averaged 15.3 days (range 11–17 days) during which each mother aphid produced on average 55.2 and 56.2 nymphs on the two bean varieties, respectively. Nymphs (66.2%) were born during the daytime (0600–1800 hr), whereas only 33.8% of the nymphs were produced during the night (1800–0600 hr). There were two peaks of diurnal nymphal production, and more nymphs were born during the morning peak (0600–0800 hr) than during the mid-afternoon peak (1400–1600 hr). A very high rate of A. fabae population increase was observed.

Ethylacetate-soluble fraction of methanol extract of the stems of two cowpea cultivars TVu 946 and Vita 1 were examined by high performance liquid chromatography (HPLC) and tested for antifeedant properties for larvae of Maruca testulalis by applying the extract on the leaf discs from the susceptible cowpea variety Vita 1. Extracts derived from TVu 946 showed significantly greater feeding inhibition than extracts from Vita 1 in all the tests. HPLC analysis gave different elution profiles for the two extracts. Together, these observations implicate allelochemical factors in general, and feeding deterrents in particular, as a basis of TVu 946 stem resistance to Maruca.

Spatial dispersion of the nymphs of the jassid, Amrasca biguttula biguttula (Ishida), and the adults of the whitefly, Bemisia tabaci Genn. on F414, a Gossypium hirsutum variety, was systematic in Ludhiana (Punjab). Both the jassid and the whitefly displayed no definite pattern along the height of the plant, though a maximum number of whiteflies were recorded at middle canopy (21–40 cm from bottom). Sample sizes of 10–15 plants, selected in a statistically linear fashion represented populations of jassid nymphs and adult whitefly on all four varieties. Sampling jassid nymphs by visual counting and whitefly by split-cage were the most suitable sampling methods for local cotton growers among the various methods compared.