The Abstract in French (Résumé) published in Volume 8 Number 3 page 295 was for another paper.

This bibliography on rice leaffolders contains 886 published and unpublished references for the period 1854 to June 1987. References are arranged alphabetically by the name of author and also classified by subjects. A distribution map, tables of alternate host plants, outbreaks, resistant rice varieties, resistant wild rices, natural enemies and developmental stages, and a brief description of current status of the leaffolders are also provided.

Investigations have been made to evaluate the development of Spodoptera littoralis as affected by feeding on a standard artificial diet containing powder of some plant species known to be resistant to the infestation of this insect. Trials were also made to find out whether the effect of these plants facilitate the potency of Bacillus thuringiensis var entomocidus HD-635 vs. the target insect. The results revealed that powders of pomegranate peel, guava leaves and lemon grass, greatly affected the insect development in terms of larval duration, larval and pupal weights, deformities in pupae and moths, percentage of emergence, egg production and hatching. This may be correlated to the chemical constituents of these plants. A marked increase was observed in the potency of B. thuringiensis endotoxin preparation vs. S. littoralis when combined with some of the tested powdered plants or its extracts but in varying degrees.

Agricultural treatments mainly against cotton and rice pests put a considerable insecticide pressure on larvae and sometimes adults of several vector species. Resistances to compounds which had never been used for public health, but were currently employed in agriculture were observed among vectors. It was also noticed that resistance level in some vector species was linked to the quantity of the compound used in the same area against crop pests.

Resistance in Anopheles gambiae in Africa, in An. albimanus in Central America, in An. culicifacies and An. aconitus in South East Asia, in An. sacharovi in Turkey, in Culex tritaeniorhynchus in the Far East as well as the DDT resistance in Simulium damnosum in West Africa, seem to be associated with the agricultural practices.

On the other hand, resistance did not develop in species which, due to their ecology, were not in contact with agricultural insecticide even in areas where DDT was applied for more than 20 years in house spraying. This is the case of An. dirus and An. minimus in Thailand and An. darlingi South America.

However several important factors like Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, have developed resistance for which agricultural treatments cannot be held responsible. It would be worth saying that the rise in malaria in certain countries, such as India, is only due to the increase of insecticide in agriculture after the “green revolution”.

A function for distinguishing between the long, intermediate and short-setaed forms of Mononychellus species complex is described. The results show that the dorsal-central body setae, variable D3, with a discriminant correlation coefficient of 0.99, was the most important variable. Five other variables, lengths of dorso-central body setae Dl, D2, laterals LI, L2 and propodosomal P2, which had significant discriminant correlations (0.28 to 0.35) with the function were, however, included in the discriminant function.

The biology of Chilo partellus (Swinhoe) was studied on two resistant, IS 2205, IS 5469 and two susceptible, HC 136, ICSV1 sorghum genotypes. Significant differences were observed between resistant and susceptible genotypes in regards to larval mortality in whorl, larval period, larval weight, larval length, per cent pupation, pupal weight, fecundity per female and total life span of this pest. Growth index was also influenced by the resistant genotypes. It has been concluded that high mortality of larvae on resistant lines is due to antibiosis.

The correlations between the characters of the pest biology have been worked out and larval stage was the most important parameter influencing the total pest survival and population build-up in the succeeding generations.

The legume pod-borer, Maruca testulalis, continues to be a major limitation to successful cowpea cultivation in many countries. During the past decade, research on this insect has increased in scope and intensity at international agricultural research centres and a number of universities. The work that has been done on the biology and control of this pest at the International Institute of Tropical Agriculture (IITA) is briefly discussed with emphasis on the development of a management strategy centred around host plant resistance, and some suggestions for future research direction are given.

The ovipositional responses of the stem-borer, Chilo partellus (Swinhoe), to the maize cultivar Inbred A are greater than the maize cultivar, Nyamula. These responses are elicited by certain characters of the plants that are perceivable prior to the moth's arrival on the plants (distance-perceivable) as well as those perceivable after arrival on the plants (contact-perceivable). Distance-perceivable characters were not found to be responsible for the difference in the oviposition on the two cultivars tested.

The contact-perceivable characters of the maize cultivars differ in eliciting oviposition by moths. Contact with the cultivar Nyamula elicits much less oviposition than with the other cultivar tested.

The effect of exposing 1, 3 and 5 days old pupae to 10°C for periods of 7, 14, 21 and 28 days on the emergence, pre-oviposition and fecundity of Cryptolaemus montrouzieri Mulsant was studied. The emergence was delayed significantly when 1 and 3 days old pupae were subjected to 10°C for 28 days when compared to 5 days old pupae. The initiation of oviposition was delayed with the prolongation of holding time. The fecundity of females emerging from 5 days old pupae subjected to 10°C for 21 days was found to be significantly higher than in any other treatment.

Twenty isolates of Bacillus thuringiensis Berliner belonging to vars. kenyae, kurstaki, aizawai and ostriniae, were tested for their activity against first instar larvae of Boarmia selenaria Schiffermüller. Isolate 30-11 (serovar 3a3b, kurstaki) proved to be 8% more effective than the standard HD-l-S-1980 (serovar 3a3b, kurstaki). This isolate was 13% more larvicidal to third instar larvae than the standard. Significant lower mortalities than the standard were obtained with the isolates: 400-1, 400-2, 400-3, 400-4, 400-8, 400-11, 400-12, 400-14, 30-2, 30-12, 30-13, 30-15, Ser. 17 and BL8a8c. Isolates 400-5, 400-6, 400-7, 400-9 and 400-10 were similar in larvicidal effectiveness to the standard.

Pyrethrins I and II were extracted from five seasonal Compositae herbs collected from semi-arid and hilly areas of North India. The relative toxicity of natural pyrethrins were evaluated against Mesocyclops leuckarti sensu lato. Based on the LC50 values, the extract of the plants could be arranged as follows: Tagetes minuta > Pulicaria crispa > T. patuia > T. minuta > P. angustifolia.

Relative susceptibility of laboratory-established cultures of four populations of Dysdercus fasciatus Sign. and one population each of D. nigrofasciatus Stal., D. cardinalis Gerst, and D. superstitiosus (F.) to topical applications of cypermethrin, fenvalerate and permethrin was investigated at Kibos, Kenya. The LD50 values of the three chemicals to populations of D. fasciatus were 0.0656–0.0757, 0.335–0.469, 0.442–0.505 μg/insect, respectively, while those for D. nigrofasciatus were 0.1690–0.2541, 0.481–0.504, 0.721–0.851 μg/insect. The LD50 values for D. cardinalis and D. superstitiosus were 0.1507, 0.714, 0.798 μg/insect and 0.0991 and 0.824 μg/insect of each of the three chemicals respectively. Based on D. fasciatus from Kibos as the reference strain, the relative susceptibility values of all populations of Dysdercus species studied were small ( < four-fold) indicating that resistance was not apparent in the cotton stainers. Of the three insecticides tested, cypermethrin was the most effective judging from the high toxicity ratios between it, fenvalerate and permethrin.

Pearl millet, Pennisetum americanum L. occupies a large proportion of the area growing millets in Africa. Consequently the insect pests that attack this species have received attention over other millets. A list of the major species is presented. Actual data on losses due to insect pests on pearl millet are not readily available. Crop loss assessment methods using incidence and damage ratios are discussed. Quantitative losses determined from insecticide trials at research station are also presented.

Various aspects of the morphology, life cycle and several natural enemies of Heteronygmia dissimilis, a lymantriid defoliator of African mahogany, Khaya nyasica, were studied in Morogoro, Tanzania. This insect is a multivoltine species with at least four overlapping generations a year, all stages of which can be found from March to October. November to February are apparently spent in pupal aestivation. The September/October generation completed its life cycle from egg to adult in an average of 41 and 45 days for males (five moults) and females (six moults), respectively. On the average females produced 200 eggs. Larvae occurred in two colour variations. They are generally nocturnal feeders, skeletonizing leaflets while in the early instars and resting on foliage or bark during the day. Adults exhibit sexual dimorphism in terms of size, colour and shape. The sex factor was close to 0.5. Four species of hymenopterous parasites belonging to four families (Chalcidae, Encyrtidae, Eurytomidae and Ichneu-monidae), as well as two species of dipterous parasites (Tachinidae) were obtained from eggs, prepupae and pupae of H. dissimilis. During the rainy season, the entomopathogenic fungus Paecilomyces farinosus was epidemic among pupae.

Studies on larval movement, feeding and development of Chilo partellus Swinhoe were carried out at Mbita, Western Kenya. Larval movement away from the plant was observed during the first and third instars. Plants inoculated at the stems recorded greater larval migration compared to those inoculated at the leaf whorls. Larval feeding was greater on IS 18363 than on IS 2146, but growth rate, weight gain and efficiency of conversion into body substances were greater in IS 2146. Thus it seems that varietal susceptibility to damage by C. partellus is different from varietal suitability for growth of the larvae.

Microscopic examination of stem tissues damaged during larval feeding revealed that feeding was mainly restricted to the pith and that the vascular bundles were hardly affected.

Seedlings of apple variety, Yarlington mill, were sprayed with different sprays containing 0.1% cypermethrin, and were subjected for 15 min to 65.3 mm artificial rainfall. The effectiveness of deposits after rainfall were tested in the laboratory with neonate codling moth larvae.

Cypermethrin formulations sprayed with each nozzle were more persistent after artificial rain, when small droplets of volume median diameter (VMD = 30–70 μm) were applied by spinning discs (charged or uncharged) compared with larger droplets (VMD* = 90–160 μm) produced by air shear nozzle. No significant difference in effects was obtained between droplets by either charged or uncharged disc.

This paper reports the results of extensive pest surveys conducted on farmers' fields and pest population studies at two national research stations between 1979 and 1981 in Burkina Faso. Major findings indicate that, under normal planting conditions, infestation of the sorghum shootfly, Atherigona seccata is very low in farmers' fields. This pest appears to be restricted to research stations. Stem borer infestation is caused by a complex of species, and species predominance varies with rainfall. South of latitude 12°N, Busseola fusca is the predominant species but further north it is replaced by Acigona ignefusalis, which is a primary pest of pearl millet. Panicle damage caused by the sorghum midge, Contarinia sorghicola, varies with season; is usually very low in the dry northern Sahelian zone but severe south of latitude 13°N. Maximum midge populations occurred between mid-September and early October.

In many parts of Africa, field sorghum is attacked by a number of insect pests, notable among them being the sorghum shootfly, a range of lepidopterous stem borers, midge and a complex of head bugs. Studies on yield losses caused by these insects are scanty, yet such information is essential in formulating an IPM strategy for the crop. This study, therefore, describes the various methods of assessing and quantifying the on-farm (pre-harvest) yield losses caused by the above insect pests.