The midge, Contarinia sorghicola Coquillett, is a major pest of grain sorghum in many areas of Asia, Africa, Australia, Europe and America. Literature documenting the status of research on the biology, behaviour, and field and cage screening techniques is reviewed. Numerous germplasm entries have been evaluated and many resistant sources are identified from various midge screening programmes. A high degree of resistance was found in nine working groups viz., Caudatum, Durra, Caudatum/Nigricans-Zerazera, Caudatum/Kafir (Hegari), Nigricans, Caffrorum-Darso, Durra-Nigricans, Durra-Nandyal and Caudatum-Bicolor. The identified resistant sources and the midge resistant varieties released from the breeding programmes are listed. Studies on the mechanisms of resistance showed predominance of antixenosis for oviposition over adult attraction and variable degrees of antibiosis. The morphological characters and biochemical factors associated with resistance have been explored. Short and compact glumes which remain closed during anthesis conferred resistance. The tannin content in the ripening sorghum grain is related to resistance against the larva. The inheritance of resistance showed quantitative nature. The open and closed glume character expression indicated its dominance and recessiveness, respectively. Short glume character can be used as an useful genetic marker. Pedigree and modified pedigree breeding systems were suggested to transfer high level of midge resistance into agronomically acceptable types for selection and hybridization.

The location of olfactory and gustatory sense organs in the larvae of the American bollworm, Heliothis armigera, have been studied using the scanning and transmission electron microscopy. The olfactory chemoreceptors of the larvae are located on the antennae, mostly on the top of the second antennal segment in the form of two trichoid sensilla, two basiconic sensilla, two styloconic sensilla, campaniform sensilla and a uniporous peg sensillum. The third antennal segment bears one basiconic sensillum and two styloconic sensilla. The gustatory sense organs are located on the mouthparts including the labrum, mandibles, hypopharynx, maxillary palps and labium. Trichoid sensilla have been located on the labrum. Epipharyngeal setae as well as long short spines are located in the epipharyngeal membrane. The basal segment of the maxillary palp bears three trichoid sensilla and one campaniform sensilla. The maxillary palp also bears four styloconic sensilla on the distal portion of the lateral protuberance and one styloconic sensillum at the apex of the medial protuberance. Close to the bases of the protuberances, there are three basiconic sensilla and one campaniform sensillum. The third apical segment of the maxillary palp carries three campaniform sensilla on its lateral side, while on its top, eight small basiconic sensilla are distributed.

Floral characteristics related to pollination were studied in four species of Theobroma and one species of Herrania (Sterculiaceae) in Costa Rica. Anthesis was complete in T. cacao, T. simiarum, T. speciosum, and T. mammosum at 0615 hr following an extended period of floral development throughout the night. Flowers of both T. cacao and Herrania cuatrecusana were fully open by dawn and pollen sacs dehisced throughout the morning hours. Stigma and style receptivity, assessed by hydrogen peroxide tests, were high throughout the morning and early afternoon in T. cacao. Bagged flowers resulted in no fruit-set. When petal ligules were experimentally removed there was no change in rates of flower abortion or total numbers of aborted flowers, tentatively suggesting that these structures play little or no role in attracting pollinators. Both Theobroma and Herrania flowers possess ultraviolet light reflectance'absorbance patterns which may play a role in pollinator attraction. Uptake of neutral red stain in T. cacao and T. simiarum showed scattered glandular activity on petals and sepals, perhaps indicating location of nectaries or other secretory organs. Conspicuous glandular trichomes on the ovary, on the lower third of the style, and in a conspicuous “basal ring” between petals and sepals (most pronounced and colorful in species other than T. cacao) may be sources of both floral attractant and reward.

Differences in floral biology among Theobroma and Herrania species suggest divergence in pollination strategies. The data presented are discussed in terms of plant-pollinator specializations in the New World tropics.

The study showed three generations of the olive fruit fly from June to November 1984. Eggs were first detected in the Shami variety in early June. There were three peaks of eggs found in almost all varieties in late June, late August and late October. Highest number of larvae was found in Santa in July, and Ascolano and Kheli in August. There were no significant differences in the number of larvae per 100 infested fruits between all varieties during the first generation except Nabali. Pupae inside the fruits first appeared in Shami in July. The number of pupae inside the fruits was high in all varieties in August. Holes made by larvae falling to the soil for pupation were recorded in early August in all varieties, except Nabali where they appeared in late August and early September. During the second generation the highest number of larvae was found in Ascolano, Santa and Rase'e varieties. The recorded parasites were Opius concolor, Eupolmus urozonus, Tetrastichus sp., Trichostereresis glabra, and Lasioglassum sp. The most abundant parasites were O. concolor and Tetrastichus sp.

Seasonal occurrence of the beetle, Dirphya nigricornis Olivier, was monitored in the field for 3 years. Two coffee varieties, French mission and SL34 with capped and uncapped canopies respectively, were used to estimate the egg niches in two coffee estates at Ruiru, Kenya. The total egg niches in the short and long rainy seasons represented low infestation (1.56–8.21%), which was nearly stable throughout the study period, 1982–1984. In some cases, however, seasonal significant (P = 0.05) variety-to-variety differences existed between egg niches at each studied site. The distribution of the egg niches of D. nigricornis occurred on branches between the 1st and 21st internodes of primary and tertiary shoots of either variety. Egg niches were negatively correlated (r = −0.44 to r = −0.99, 19d.f.) to internode position in all five categories of the shoots examined. The beetle therefore concentrates infestation and does not place its progeny randomly on coffee shoots.

Experiments were carried out to study the effect of sublethal doses of gamma radiation (10–100 krad) on fecundity, longevity and sterility of adults of Silotroga cerealella. The results indicate that fecundity of females decreased as the dosage increased from 10–90 krad. At 100 krad no eggs were deposited. Raising the dose to 100 krad resulted in shortening the longevity to about half the longevity of the untreated moths. When irradiated females mated with similarly irradiated males, a dosage of 20 krad caused 97.17% sterility. A dose of 28 krad induced 96.69% sterility when normal females were mated with irradiated males, while 94.14% sterility resulted when normal males were mated with irradiated females.

Eleven artificial diets with principal base-ingredients as pulses and beans, viz. winged bean, Psophocarpus tetragonolobus; green gram, Vigna radiata (L.) Wilczek; dew gram, Vigna aconitifolia (Jacq.) Marichat; broad bean, Vicia fabia (L.); soybean, Glycine max Merr.; and cluster bean, Cyamopsis tetragonoloba Taub., were formulated either alone or in combination, for the mass rearing of Chilo partellus (Swinhoe). On the basis of important biological parameters having direct bearing on the selection of media for rearing, seven diets were unsuitable. These diets were compounded with either winged bean, soybean grains (dry and water soaked), or broad bean or with different quantities of cluster bean blended with green gram and dew gram as principal base-ingredients. The superiority of the remaining four diets based on (i) kidney bean, (ii) kidney bean + sorghum leaf powder, (iii) green gram + dew gram, and (iv) green gram + dew gram + sorghum leaf powder, was established. The modified green gram + dew gram + sorghum leaf powder-based diet has an added advantage over its original version due to low cost of production of moths and eggs in both the generations. This highlights the formulation of a new modified diet which can be utilized not only as an alternative to the original green gram + dew gram based diet but also can replace it to overcome the phenomenon of inbreeding depression due to continued rearing in the same diet.

Twelve models are presented to examine the feasibility of using pheromone baited traps containing chemosterilant for pest control, and to compare the efficiency of this method with the use of (i) pheromone baited traps containing insecticide, and (ii) sterile releases. It was found that the number of matings per individual has little effect on the efficiency of population control, whereas immigration of even a relatively small number of the pest species severely limits this method in its ability to control the population. The existence of density-dependent regulation on the other hand greatly enhances the effectiveness of this control method. If the birth rate greatly exceeds one young per adult per day, then the method using chemosterilants is approximately twice as efficient as either insecticides in the pheromone traps or the release of sterile males. However, if the birth rate is much less than one per day, as in tsetse, then chemosterilants are very much more efficient than either method. These differences in relative efficiency appear to depend on the frequency of mating relative to the birth and mortality rates.

This bibliography on diseases of insect pests of rice contains 287 references. Major groups of insect pathogens are briefly discussed. Available records on diseases, insect hosts and locations of collections are tabulated. Additionally, references are grouped by subject.

Most fifth instar Argina cribraria female larvae reared in paired groups on fresh sunnhemp leaves practised cannibalism on the male. A potential cannibal pounced on the victim and severed its dorsal vessel, causing profuse bleeding of haemolymph, immobility and contraction. The cannibal fed on victim's carcass and might consume 1–2 larvae and 1–3 pupae. More females emerged from an experiment having larval cannibalism. The cannibals were lighter, but the relative titres of sugars, proteins and phenols were higher in cannibals than those in control female caterpillars.

Haemocoelic injections of live Escherichia coli and oral administration of three tetracycline compounds, namely Reverin, Maxitet and Terramycin to female Glossina morsilans morsitans prior to their first larviposition, caused a decrease in fecundity, but had no effect on longevity. Trypanosoma brucei brucei and T. congolense administered by haemocoelic injections, however, caused no change in fecundity or longevity, but tsetse infected with T. b. brucei and T. congolense in their mouthparts had decreased fecundity and longevity as compared to controls.

Steam distillates of seven Nigerian plants, Lippia adoensis Hoschst, Azadirachta indica A. Juss, Monodora tenuifolia Benth, Piper guineense Schum & Thonn, Petiveria alliacea L., Citrus sinensis L. (variety Nigerian green orange), and Cymbopogon citratus L. were tested for acute toxicity on four major insect pests. The pests were larvae of Acrae eponina Cramer, adult cotton stainer Dysdercus superstitiosus (F.), the cowpea flea beetle, Ootheca mutabilis Sahlberg and the pod sucking bug Riptortus dentipes F. Essential oils of L. adoensis, M. tenuifolia and P. guineense were toxic to the insects. O. mutabilis was the most susceptible with LD50 of 0.15, 0.32 and 0.52 respectively for M. tenuifolia, L. adoensis and P. guineense, while R. dentipes was the least susceptible. There was cessation of feeding in A. eponina treated with essential oil of C. sinensis and P. alliacea.

Oviposition and development of Evania appendigaster and Tetrastichus hagenowii in live P. americana oothecae ranging in age from 0–44 days was investigated. E. appendigaster oviposited in oothecae of all ages but developed only in 0–28 days old oothecae. T. hagenowii oviposited only in oothecae 0–34 days old, but developed only in 0–28 days old oothecae. Oothecae parasitized by E. appendigaster were superparasitized only during the first 4 days after the initial parasitization. A single parasite emerged from each such oothecae, indicating that only one of the two ovipositions was successful. Oothecae superparasitized by T. hagenowii during the first 8 days of the initial parasitization, resulted in ca. 90 parasites from both ovipositions. Oothecae parasitized by each species of parasite were subjected to multiple parasitism by the other species. Oviposition of E. appendigaster in 0–25 days old oothecae, parasitized by T. hagenowii was ineffective as it resulted in the emergence of T. hagenowii only. Reparasitization of 0–36 days old E. appendigaster-parasitized oothecae by T. hagenowii within 0–32 days resulted in the development of T. hagenowii, but reparasitization thereafter was ineffective as only E. appendigaster emerged. Even though T. hagenowii is more efficient than E. appendigaster, in parasitizing and developing in different types of P. americana oothecae, under field conditions the two species of parasites contribute equally towards the natural control of P. americana.

Abdomen homogenates of refractory C. quinquefasciatus and Anopheles stephensi prepared from equal and varying wet weights of abdomen, were shown to inhibit endopeptidase induced in vitro exsheathment of Brugia pahangi microfilariae. This inhibitory effect was removed by heat treatment and centrifugation of the homogenates. Abdomen homogenate from susceptible Aedes aegypti did not inhibit exsheathment. This suggested the presence of some inhibitory factor in the abdomens of the two insusceptible species of C. quinquefasciatus and An. stephensi. There was no evidence of this inhibitory effect in the midgut homogenates of the three mosquito species. Foetal calf serum and bovine serum albumin also inhibited endopeptidase induced exsheathment of B. pahangi microfllariae, suggesting that the protein concentration of the proteinaceous substances also determined the extent of inhibition. In the absence of endopeptidase, incubation in midgut homogenate of the 3 species of mosquito did not initiate exsheathment, suggesting that the conditions present in vitro did not simulate those persisting in the mosquito midgut in vivo.

Infection of Diacrisia obliqua larva by Apanteles flavipes resulted in a significant decrease in the lipid and protein content of the host. In about 8 days the parasitoid larvae developing in the host not only utilized these components of the host but also depressed food consumption of the host. Consequently, at the time of emergence of the parasitoid larvae, the host tissue consisted of simply carcass. The parasitoid larvae utilized lipids at the rate of 0.9–10.0 μg/mg/day.

Recent surveys have shown that ant-Homoptera associations are not limited to cocoa trees only but a large number of other plant species serve as hosts for such associations. It has been observed that some ant species may tend more than one Homopteran species on a number of different host plants. Seasonal abundance of the homopterans and their tending ants was studied on cocoa, mango and pigeon pea.

The populations of the ants tend to synchronize with the populations of the Homopterans which they tend during the season.

Electrophoretic variation was determined at eight enzyme loci in Anopheles arabiensis from four villages in Mwea Irrigation Scheme, Kenya. Seven loci had polymorphic alíeles of which at least two were common. Pooled allele frequencies at the Pgm, β-Had and Odh loci were in Hardy-Weinberg equilibrium, while those at the Ao, Idh, Adh, Est-1 and 6-Pgd loci showed significant deviations. The frequency of heterozygotes at the Adh, Est-1 and 6-Pgd loci was less than expected, while at the Ao locus, there was an excess. A 2 × 4 contingency χ2-test for each of the loci not in Hardy-Weinberg equilibrium indicated an association between the respective gene frequencies and the villages. The suggested explanation for these observations is that each village constitutes a distinct population, and that the pooled data introduced the Wahlund effect. Allele frequencies at individual loci per village population are most likely at Hardy-Weinberg equilibrium. Larger samples per village need to be examined to facilitate a goodness of fit χ2-test between observed and expected frequencies.

The field experiments were conducted during the summer of 1985 to determine the degree of winter wheat resistance to the grain aphid Sitobion avenae. Asta, Grana, and Saga cultivars were generally more resistant than Dana, Liwilla, and Emika. The resistance mechanism involved both antixenosis and antibiosis. Grana was least preferred during aphid migration. Asta, Saga, and, to a lesser extent, Grana had an antibiotic effect on growth and development of the apterous aphids (longer prereproductive period, lower fecundity and lower values of the intrinsic rate of increase, rm, during the first days of reproduction). Moreover, var. Asta showed a “secondary antixenosis” during colonization of ears due to the presence of awns.

Six transformations viz., , log[log (x + 2)] and log[log (x + k )] were tested for their efficiency in stabilizing variance of Coccus viridis (Green) population counts which followed negative binomial distribution. Only log[log(x + 2)] transformation was found effective in stabilizing variance. This is a new transformation proposed by the authors.

Literature on the distribution, biology, seasonal population fluctuations, economic importance, acaricidal susceptibility and measures for the control of the cattle ticks Boophilus microplus Canst., Amblyomma cajennense Fab., A. variegatum. Fab. in the Caribbean has been critically reviewed. The ticks, which inflict about $62 million annual loss on the region's livestock industry, are still susceptible to acaricides, despite a few populations of B. microplus showing 31- to 227-fold resistance to lindane and 15- to 67-fold resistance to carbaryl, chlorfenvinphos, dimethoate and crotoxyphos.

The screwworm, Cochliomyia hominivorax Coq. is widespread, except in Puerto Rico and Curacao, from where it has been eradicated. The annual cost of surveillance against the fly and treatment of cattle for myiasis is estimated to be about $59 million. Its eradication from the entire Caribbean region by insect sterile method is advocated.