The effects of cyanocobalamin on the protein, RNA and DNA contents of ovary of silkworms, Bombyx mori L., were investigated. Two sets of experiments were performed, one set dealing with the changes on some selected days in protein, RNA and DNA contents after a single injection of different doses of cyanocobalamin (0.25, 0.5, 1, 2 and 5 μg/g of body weight), given on 2nd day of fifth larval instar (day 0), and the other dealing with the day-to-day variations of these cellular constituents and the effect of a particular dose (2 μg/g) of cyanocobalamin on the daily changes of the substances. In the first set of experiments, the enhanced protein content of ovary over the control value was found on day 8 (2nd day of pupa) and day 13 (adult stage) with 1, 2 and 5 μg of cyanocobalamin/g. Cyanocobalamin at the dose of 0.25 and 0.5 μg/g was ineffective in causing any change in protein content. Increased RNA content was noted in comparison to the control on days 3 (5th day of fifth instar), 8 and 13. In case of DNA content of ovary, the enhancement was observed on days 8 and 13 with 1, 2 and 5 μg/g doses. It was further evident from day-to-day changes that protein, RNA and DNA in ovary followed a specific individual pattern of changes during the developmental period under study. Cyanocobalamin at the dose of 2 μg/g increased protein content of ovary from day 5 to day 13, RNA content from day 3 to day 13 and DNA content from day 4 to day 13 without altering the specific pattern of variation of these cellular constituents. It was further observed that ovarian weight and egg number increased with different doses (0.5–5 μg/g) of the vitamin.

Two monoclonal antibodies (Mabs), that react in an enzyme linked immunoabsorbant assay, were generated against Aedes aegypti vitellin. One of these Mabs, VIIG9 that reacted predominantly with a 64 kDa component of Ae. aegypti yolk protein, also recognized 68 kDa and 66 kDa components in the yolk proteins of Culex sitiens and Cx. annulirostris, respectively. Mab VIIG9 has been used to detect vitellin or vitellin precursors in gravid female and non-blood fed nulliparous female mosquitoes as a possible age grading method. The presence of polyclonal and monoclonal antibodies to vitellin in the blood meal did not affect the fecundity of Ae. aegypti.

The insecticide activity of synthetic pyrethroids to Triatoma infestans was tested by topical application. Deltamethrin, fenpropathrin, bioresmethrin, permethrin, cypermethrin, d-phenothrin and cyphenothrin showed the highest activity.

The susceptibility to poisoning of adult insects by these pyrethroids (except bioresmethrin) was increased by cotreatment with profenofos or with piperonyl butoxide (PBO). Assayed pyrethroids synergized by PBO showed similar general structure.

The vinyl cyano pyrethroids showed a knockdown effect with a delayed recovery. During 15 days after intoxication with deltamethrin, insect recovery was observed. Recovery blockage by PBO was observed in cyphenothrin and deltamethrin poisoning at low doses.

Xenopsylla astia, the indigenous commensal rat flea has been replaced by X. cheopis in many parts of India to a large extent. As a result of this replacement or suppression serious outbreaks of plague had occurred in the country in the earlier part of the century. The introduction of DDT for malaria control programme, as a collaboral benefit, has also served to control plague in the country. This has also encouraged DDT resistance in fleas. In the present paper the distribution of X. astia in the state of Maharashtra is discussed along with its susceptibility status to DDT. The distribution of this flea now appears to be patchy, being restricted to very few areas. The flea demonstrates high degree of resistance to DDT.

I would like to extend my expose to cover also dry pulses and groundnuts which make up, together with cereals, the greater part of grains stored at farm and village level.

To begin with, we should make a distinction between, on the one hand, countries with a rather good road network and more or less workable grain marketing institutions, where farm storage has much decreased and in some cases nearly vanished, and on the other hand, countries where the isolation of producers and absence of good marketing institutions have helped to conserve the traditional storage methods on the farm, and occasionally, in the villages. As examples of the first type of countries, I would indicate Kenya and Zambia and of the second type, Chad and a large part of the Sudan.

In southern India, the principal tea pests such as the mites, Acaphylla theae, Calacarus carinatus and Oligonychus coffeae; the thrips, Scirtothrips bispinosus; the aphid, Toxoptera aurantii; and the caterpillars, Caloptilia theivora, Homona coffearia and Cydia leucostoma are attacked by many natural enemies. H. coffearia is efficiently controlled by the ichneumonid, Phytodietus sp., and the tachinid, Palexorista solennis, whilst the eulophid, Sympiesis dolichogaster, affords excellent regulation of C. theivora. The braconid, Apanteles aristaeus, is the chief parasitoid of C. leucostoma, but the efficiency of this species is rather low. The aphiidids, Aphidius colemani, Lipolexis scuttellaris and Trioxys indicus, and several species of coccinellids and syrphids exert tremendous influence on the populations of T. aurantii. No natural enemies of the scolytid stem borer, Xyleborus fornicatus, could be recorded. For the management of mites, pesticides are applied regularly and the widespread usage of broad spectrum acaricides such as dicofol and sulphur is an important reason for the low incidence of predatory mites in tea fields.

Eight cultivars of the common bean (Phaseolus vulgaris L.) and the Tepary bean (Phaseolus acutifolius) were used to study the distribution of puparia of the bean fly species Ophiomyia phaseoli (Tyron) and O. spencerella (Greathead). The puparia of the two bean fly species were distributed differently in the plant, O. spencerella predominating in the root and O. phaseoli in the shoot. There were significant differences between some of the bean cultivars and the number of puparia found. Tepary had the least puparia and P. vulgaris cultivars GLP 806 and GLP 1131 the most. There was a low correlation between the number of puparia and the final yield or root dry weight.

The relative susceptibilities of 43 cowpea varieties to damage by Cydia ptychora (Meyrick) under chemical protection with monocrotophos, were investigated in field trials at Ile-Ife, Nigeria. The results revealed significant varietal differences, with the moderately resistant varieties ER-7, BPL-3-1 and EW/1 consistently showing relatively low damage. These varieties may be useful in planning an integrated pest management programme involving minimum insecticide treatment.

After the rinderpest panzootic of the late last century, Southern Mozambique appeared to have become free of Glossina morsitans and G. pallidipes. However, since the 1940s a gradual advance of tsetse into Southern Mozambique has been observed. Anti tsetse measures were taken during the 1950s and 1960s along the southern front of the tsetse belt to stop the advance of the fly into tsetse free cattle grazing areas.

To reassess the extent of the fly front in Inhambane Province, a tsetse survey using bait oxen was made in the Muabsa area during 1981 and 1982. G. m. morsitans, G. pallidipes and G. austeni were found, although not always sympatrically. It appeared that the G. morsitans and G. pallidipes front in the study area had been stable since 1969. The front is situated along a line of marked changes in soil and vegetation types and it is concluded that this may be the reason why these tsetse did not advance further south. G. austeni was found throughout the study area in a less well defined belt. The populations of G. m. morsitans and of G. pallidipes in the study area form the most southerly distributed populations of these species known in Africa today.

Seven benzyl-1,3-benzodioxole analogs were tested for possible effects on reproduction in females of the Mediterranean fruit fly. Single topical doses of J2581 (5-ethoxy-6-[4-methoxyphenyl]methyl-1,3-benzodioxole) and J3263 (5-methoxy-6-(1-[4-ethoxyphenyl]ethyl)-1,3-benzodioxole) were found to cause a temporary delay in ovarian growth in female medflies by 9 and 13 days respectively when compared to acetone-treated controls. Continued exposure of the analogs at the target site(s) appears to be necessary for more permanent effects. Nurse cell development appears not to be affected, but oocyte growth and subsequent egg production and egg hatch were significantly reduced. Methoprene treatment appeared to obviate the effect of J2581 in arresting ovarian growth.

The green cassava mite, Mononychellus tanajoa (Bondar) and the red spider mite, Tetranychus urticae Koch infest all varieties of cassava in Sierra Leone. Both tetranychid species are widely distributed in the country and are causing severe damage to the crop mainly in the major cassava producing areas in the north-western regions. M. tanajoa caused chlorosis and 91° loss in photosynthetic area of the attacked leaves and defoliation of the plant either by acting alone or in concert with T. urticae. Late planted crop was particularly vulnerable to the infestation. M. tanajoa and T. urticae appeared to avoid severe interspecific competition on the plant by habitat stratification.

A study of the effect of microenvironment on the pea leaf weevil's behaviour was made comparing a broad bean monoculture with a broad bean-oat crop mixture. It is observed that more weevils depart from the crop mixtures than from the monocultures. Microenvironment study in the two cropping systems show that temperature and wind speed are not significantly altered in the crop mixtures as compared to the monoculture, but beans growing in the mixtures were significantly more shaded than those in the monoculture. Evidence is given to show that this relative shading could be the main factor responsible for the observed increased weevil departure from the crop mixtures.

Trials for cold storage of the mummies of Aphis craccivora Koch parasitized by Trioxys indicus Subba Rao & Sharma were made. Newly formed mummies having fourth instar larvae of the parasitoid were put either at 20–25°C or at 12–15°C, 10 hr photoperiod for 24–72 hr before storage inside the refrigerators (4–8°C) for 10–40 days. A higher proportion of adult emergence was usually associated with the group of mummies passed at 12–15°C before storage and practically good emergence was recorded even if the mummies were stored for a month at 4°C if kept at 12–15°C for 72 hr prior to storage.

Six cowpea cultivars, TVu 1890, TVu 1, TVx 3343-03E, IT82E-9, VITA-3 and Ife Brown, with different responses to infestation and damage by pod-sucking bugs (PSBs) were studied for the biophysical and biochemical characteristics of pod that may be involved in this differential response to feeding by PSBs. Tough pod wall, requiring a force of 25 newtons/mm2 to penetrate at pod maturity, is considered to be an important factor contributing to the lesser PSB feeding damage observed in the cultivar TVu 1890. The phenolic content of the pods of the studied cowpea cultivars was not correlated with their tannin content. Furthermore, no correlation could be established between the tannin content in the pod and the level of susceptibility of the cowpea cultivars to infestation and damage by PSBs. While tannins are considered to be important in conferring certain types of anti-herbivory properties to a number of plants and crop varieties, our findings suggest that in the cowpea cultivars studied, phenols in addition to the tough pod wall may be more important in conferring resistance to PSBs.

Different concentrations of essential oil of lemon grass, Cymbopogen citratus, were tested for their ovipositional inhibition, antifeedant activity and insecticidal properties against the lesser cotton leafworm, Spodoptera exigua. The results obtained showed that 2% concentration of oil emulsion inhibited egg laying and 0.5% concentration more than reducted by 70% the number of eggs deposited on oviposition sites. 2% concentration acts as a protective concentration against the immature stage by hindering the third instar larvae to feed on treated leaf discs. In addition, the oil emulsion was insecticidal in that percentage mortality was directly proportional to the concentration applied and to the duration of exposure. Older egg masses were more affected by treatment than the newly laid eggs. 2% concentration inhibited hatchability when sprayed on egg masses before hatching. Lemon grass oil effectively controlled S. exigua as an ovicidal and larvicidal agent.

FAO has in the past given much attention to the development, dissemination and use of methods to assess pre- and postharvest crop losses. The experience gained shows that losses vary with location, crop, pest and differ from year to year. The collection of data on a national or regional basis is expensive, since data have to be collected over a number of years. Therefore, loss assessment is now mainly used as a tool to develop loss reduction strategies and to assesss the cost-effectiveness of introduced methods.

A reservation is made with respect to the quoting of data on losses, without giving information on how these data were collected and interpreted, because data presented in that way can easily be misinterpreted.

Many useful crop preharvest loss assessment methods are presently available for the researcher, but there is, however, an urgent need for simple methods for use by extensionists and farmers in other situations. The developed methods to assess postharvest losses in grains are adequate.

Studies on the spatial distribution and sampling of infestation of the blister midge, Erosomyia indica Grover, were carried out in a mango orchard at Bangalore, India. The spatial distribution of the infestation on the panicles were studied using the parameters variance-mean ratio, and Lloyd's index of patchiness. It was found that the midge infestation tended to follow a random distribution pattern. The infestation was not significantly different among the sections of the canopy delineated horizontally and vertically. However, infestations in east lower, south lower and south upper were significantly correlated to the total infestation. The sample sizes were apportioned to these sections using regression analysis, thus arriving at a sectional random sampling plan for better precision estimates. For the data on percentage infestation, angular transformation was found to be satisfactory. These results have application in field studies leading to the management of the pest on mango.

This paper describes the immature stages of the striped caterpillar Epicerura pulverulenta Hampson, a notodontid defoliator of combretaceous trees, viz., Terminalia ivorensis, T. superba, T. catappa and Anogeissus leiocarpus. The structure and chaetotaxy of the mature (fifth stage) larva is described in detail with illustrations to aid easy field identification of the moth.

In a screen cage study, the pattern of flower and pod development at the various flowering nodes of three cowpea varieties with known susceptibility to the pod-borer Maruca testulalis, was mapped out. The period of flower opening over the whole plant spanned an average of 13 days in TVu946, 17 days in ICV-2 and 18 days in Vita-1 with 85–100° of the pods retained to maturity coming from flowers opening within 8 days of anthesis. The efficiency of pod production from open flowers was highest in TVu 946 (54°), lowest in Vita-1 (11°) and median in ICV-2 (31°). However, as a consequence of the individual pod size, the overall pod and seed characteristics in decreasing order were Vita-1, ICV-2 and TVu 946. The bulk of flowers and pods on the plants were produced at the basal plant nodes where primary branches were developed.

Pod elongation and enlargement were initially rapid in all varieties, but the TVu 946 pods reached physiological maturity 2 days before the other two varieties. The eventual pod size and rate of pod growth appear to be important factors in the susceptibility of cowpea to the pod-borer attack.