This selected bibliography on the whitebacked planthopper, Sogatella furcifera (Horváth), contains 506 published and unpublished references for the period 1899 to February 1984. References are arranged alphabetically by the name of the author and also classified by subjects. A distribution map, two tables of the varietal resistance to the pest and its natural enemies, and a brief description of the current status of the pest are also provided.

Female Eldana saccharina Walker was found to lay 327 ± 17.1 eggs within a period of 4 days and required three surfaces to lay eggs which were mainly deposited on the inner side of leaf sheaths fitting tightly on to the sugar-cane stalk. The mated females laid more eggs per female (327.0 ± 17.1) than virgin females (212.3 ± 5.5). The incubation period of the eggs of E. saccharina was found to be 5.64 ± 0.01 (5–7) days in the laboratory and 5.82 ± 0.03 (5–7) days in the field. The mean larval duration was 31 days and pre-pupal period lasted 2.05 ± 0.05 days. Larvae were found to exude a brownish liquid from their mouth in the direction of the invading predators. The newly hatched larvae spread out in 1–3 days of hatching. The mean growth ratio of the larval instars was 1.54 ± 0.05. Pupae frequently occurred very close to the exit hole (less than 5 cm) and the pupal period varied from 7 to 13 (9.76 ± 0.05) days. The life cycle of E. saccharina was completed in 49 (36–62) days. The pre-oviposition period was 2 days and the female reproductive life lasted 4 days. It takes about 53 days for a succeeding generation to be produced. Adults of E. saccharina survived from 6 to 13 days. Adults reared from field collected larvae snowed a sex ratio of 42:51 which was significantly different from 1:1 in the laboratory bred stock, at the 5% level of probability. A comparison of the life cycle of E. saccharina populations in Ghana and Uganda suggests the existence of two biotypes of the pest.

Feeding of the adult parasite of Trichogramma evanescens Westwood on a honey solution containing 500 μg of Bacillus thuringiensis var. galleriae HD-129 for 4–5 days had no effect on their longevity, productivity or their capability to parasitize the host eggs of Spodoptera littoralis (Boisdüvalle) or Anagasta kuehniella Zeller. After spraying the freshly laid host eggs with B. thuringiensis at the same concentration, a significant decrease was observed in the percentage of parasitism. No deleterious effects were observed in the development of the immature stages of the parasite and the percentage of its emergence, as affected by B. thuringiensis, when applied to the host eggs before or after parasitism.

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 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.

Sixty selected rice varieties were tested for resistance to damage by the African striped borer, Chilo zacconius. Artificial infestation with first instar larvae in screenhouse showed that Lac 23 (white), IR 2035-120-3, 1R 4625-132-1-2, Colombia 1 and N 21-1 had significantly low “dead hearts” and larval survival. Damage was also low when these varieties were exposed to adults in the screenhouse and in the field. Both local and exotic varieties possessed resistance. Antibiosis conferred resistance to the borer in the varieties screened.

There are five caterpillar instars in the life cycle of Spodoptera exempta (Walk.) when they feed upon star grass, Cynodon dactylon (L.) Pers., maize, Zea mais L. and Kikuyu grass, Pennisetum clandestinum Chiov. at 25–30°C. When the temperature is 18°C, however, there was an additional instar in the cycle. Similarly extra instars are formed on Guinea grass, Panicum maximum Jacq., Setaria plicatilis (Hochst.) Hack, and a sedge, Cyperus maranguensis K. Schm. even when the temperature appears to be sufficiently high for normal development. Occasionally the additional sixth instar is also too small to pupate, in which case a seventh instar is formed. It appears that caterpillars on nutritionally inadequate host plants or those at low temperatures are being partially starved and must continue moulting until the appropriate size is attained or exceeded. Measurements of the head capsule widths or distances between the frontal clypeal setae suggest that only individuals reaching or exceeding a species specific threshold size pupate. Extra moults appear to be an adaptation to environmental fluctuations obtaining within the range of occurrence of S. exempta.

The biology of the aphid, Cerataphis variabilis H.R.L., on Raphia hookeri Mann & Wendl., was studied in the laboratory and the field using a ‘clip-on’ cage and a sleeve cage. The first instar lasted 5.1 days. The second and third instars each lasted 2.45 days, while the fourth instar lasted 2.4 days. The total developmental period of the nymphs was 11.3 days at 26.4 ± 1.43°C and r.h. 83 ± 1.46%; 11.6 days at 26.4 ± 1.63°C and r.h. 85 ± 1.19%; 12.9 days at 27.9 ± 1.04°C and r.h. 75.5 ± 1.64%; 12.95 days at 27.8 ± 0.33°C and r.h. 69 ± 1.23%; 15 days at 21.4 ± 0.58°C and r.h. 45 ± 1.77%. These periods were significantly different at 5% level (LSD = 0.59 days). The higher the temperature and relative humidity the shorter the developmental period (with temperature: r = −0.69, 20.8–28.9°C; r.h.: r = −0.97, 43.2–86.2%). The number of progeny per adult ranged from 54 to 60 in a period of 28–31 days. The longevity ranged from 31 to 34 days.

The use of surfactants and their blends to improve the penetration of two insect growth regulators (IGRs; hydroprene and R-20458) into wheat kernels was investigated. It was found that formulation of IGRs with a surfactant, Tween-85 (polyoxyethylene trioleate), increased mortality and/or effectiveness of the IGRs. Formulation of hydroprene with a blend of Span-80 (sorbitan monooleate) with Tween-80 (polyoxyethylene monooleate) produced results comparable to those by hydroprene with Tween-85. However, formulations of IGRs with surfactants with high or low hydrophile-lipophile balance (HLB), failed to provide suitable control of the weevil, probably due to the type of emulsions formed. The same results were obtained with hydroprene formulations with blends of Spans and Tweens, even though their HLBs were close to that of Tween-85. Residual half-life for hydroprene was about three months; formulations with Tween-85 or a blend of Span-80 did not enhance the residual activity for hydroprene in wheat.

Ground spraying trials with different dosages of deltamethrin wettable poweder (NRDC 161) were carried out against G. palpalis (s.l.), vector of sleeping sickness, in January and November 1981 in the Bouaflé human trypanosomiasis focus, Ivory Coast. Three dosages have been tested: 60 g of active ingredient (a.i.) per ha at a concentration of 0.08% in January; and 20 and 12 g of active ingredient per ha in November at 0.027 and 0.016%, respectively. Each dosage has been applied once as a residual spray; spraying apparatus used was the atomiser Solo Port 423. The knock-down and short-term effects of the insecticide were very satisfactory: 90–98% reduction in apparent density of the vector was obtained during the first 2 months after treatment with all the three dosages applied. In the long term, 2–4 months after spraying, more than 95% reduction in apparent density of G. palpalis (s.l.) was achieved even with the lowest dosage of 12 g (a.i.)/ha. The highest dosage of 60 g (a.i.)/ha does not seem to increase significantly the persistence of the insecticide nor the mortality rate of the vector in the study area. In order to reduce the cost of a tsetse control programme and also to minimise insecticide impact on non-target organisms, it is therefore recommended that deltamethrin w.p. be applied at the lower dosage of 12 g (a.i.)/ha in residual ground spraying.

The life history of Amblyseius fustis (Pritchard and Baker) was studied in the laboratory at a fluctuating temperature and relative humidity ranging from 24.4 to 28.0°C and 55.5 to 75.6%, respectively. The developmental stages consist of egg, larva, protonymph, deutonymph and adult. The life cycle, from egg to adult of both male and female was about 8 days, while longevity was about 19.2 days. Mated female laid an average of 18.8 eggs. There was no significant difference in the longevity and fecundity of predators fed on different life stages of the host. The proportion of male to female in the progeny of mated females was 1:4.

A. fustis has a shorter developmental period and lives longer than its prey, but the latter is more fecund (26.9 eggs/♀) and has a higher proportion of females in its progeny (1:4.8). The shorter developmental period and the longer life span of the predator are likely to offset the higher fecundity of the prey.

A survey of the natural enemies of the main malaria vector in Kenya, Anopheles gambiae Giles, revealed the occurrence of a fungal pathogen in field populations of mosquito larvae. Light and scanning electron microscopy was used in the examination of sporangia of the fungus in determining its identity as Coelomomyces indicus Iyengar (Order: Blastocladiales; Family: Coelomomycetaceae). The resting sporangia were found in the thoracic and abdominal cavities of the larvae. A mortality of 63% or higher was found to occur among the larvae of A. gambiae in a two season observation along the Kenyan coast. The authors stress the need for more intensified ecological and laboratory studies aimed at developing C. indicus as a biocontrol agent.

Insect-free tubers of four potato varieties, namely Kenya Baraka, Anett, Kerrs Pink and Roslin Gucha were exposed to adult Phlhorimaea operculella for 14 days in uncontrolled conditions in storages. On examination of the tubers 16 days after exposure, the percentage of infested tubers was determined: Kenya Baraka—62.50, Anett—77.50, Kerrs Pink—85.00 and Roslin Gucha—86.25%. The larvae made the following mean tunnel lengths: 44.65, 95.33, 88.33 and 104.23 cm in Kenya Baraka, Anett, Kerrs Pink and Roslin Gucha varieties, respectively. Although there were no statistically significant differences in the number of tubers infested (per cent), there were significant differences in the mean length of tunnels made by the larvae in Kenya Baraka and the other three varieties at P < 0.05. The mean number of larvae which survived in 10 tubers were 6.75, 11.25, 15.75 and 18.00 for Kenya Baraka, Anett, Kerrs Pink and Roslin Gucha varieties, respectively. There were statistically significant differences between Kenya Baraka and Kerrs Pink; Kenya Baraka and Roslin Gucha; and Roslin Gucha and Anett varieties (P < 0.05). Thus Roslin Gucha was the least resistant of the four varieties tested, whereas Kenya Baraka emerged as the most resistant variety. The mechanism of resistance in this case was most probably antibiosis.

The persistence of 34 formulations in the green (G) and red (R) berries of C. arabica var. typica, infested with female adult H. hampei were assayed by a dip-technique. The 3-day LC50 values in G and R (figures in parentheses) berries for thiodan EC 35 were 0.00284 (0.00327), and the relative ratio of values for other formulations were: perfekthion 1.2 (2.1) > carbicron 1.6 (2.3) > basudin 3.5 (3.2) > actellic 4.0 (3.6) > decis 4.1 (3.7) > thiodan EC 3 4.2 (4.2) > bidrin 5.8 (5.0) > malathion 5.8 (5.1) > lindane 5.8 (5.6) > ciodrin 5.9 (5.6) > folimat 6.0 (6.0) > belmark 6.2 (6.3) > aldicarb 8.0 (9.7) > nexion 11.0 (12.0)>kelthane 13.5 (15.4) > tiovel 14.6 (16.3) > dursban 15.6 (22.0) > chlordane 17.8 (23.8) > methomyl 21.5 (24.3) > aldrin 25.1 (24.9) > supona 27.2 (26.5) > dimilin 29.0 (27.5) > methoxychlor 31.7 (92.2) > chlorfenvinphos 35.8 (92.5) > dieldrin 41.2 (93.8) > phosdrin 65.0 (94.7)>sevin 104.2 (118.0)> nexagan 106.4 (121.9) > bimarit 196.4 (301.7) > azodrin 271.2 (410.4) > fenitrothion 448.3 (417.0) > chlorpyrifos 448.8 (614.3) > gardona 514.6 (703.1), -fold more than the thiodan EC 35 values.

The 7-day LC50 values for 29 formulations were ca 10–82% less than those of the 3-day values; the decrease in the values for leading formulations being thiodan EC 35 13.4 (8.3), perfekthion 6.5 (39.9), carbicron 12.4 (10.6), thiodan EC 324.3 (16.4), malathion 35.2 (25.7), lindane 82.1 (76.9) and tiovel 59.6 (67). The values for the 17 least toxic formulations (except dimilin and bimarit) showed ca 27–88% decrease during the last 4 days of observations.

The distribution of Rhipicephalus appendiculatus on Setaria sphacelata flowerheads was investigated. Adult tick counts in a paddock, heavily infested with ticks for experimental purposes, revealed an aggregated distribution by deviating significantly from the expected Poisson distribution, but producing a good fit to the expected negative binomial distribution. A higher proportion of the ticks were on old dry flowerheads than on young green ones. Tests carried out in the laboratory confirmed the marked preference for old flowerheads and the aggregated pattern of distribution. The tick counts in the field revealed no sexual aggregation, though the total number of females collected was significantly higher than that of the males.

The efficacy of natural embelin isolated from berries of Embelia ribes Burm. against Tribolium castaneum Herbst is discussed. Embelin mixed with wheat samples at concentrations of 0.1875% and above exhibited high efficacy by bringing about adult mortality even after 8 months of storage. Productivity (progeny/adult-day) of the test insect was also reduced significantly in treatments as compared to controls at different intervals of storage. After 8 months of storage, significant reduction in F1, progeny at the lowest concentration was mainly due to larvicidal action of embelin. In the present study, embelin did not exhibit any chemosterilant action or contact toxicity to adult beetles. Germination of wheat treated with embelin even at the highest concentration of 0.750% was not impaired to any significant extent.

Loss estimates for wheat insects in Africa and Asia have not received adequate attention. However, in PDR of Yemen, pests including insects, diseases, weeds and birds can cause 10™70% loss of wheat crop. Aphids are considered to be the major insect pests of wheat in the country. A survey of indigenous natural enemies has shown that they may contribute to overall aphid control. Sowing date experiments have shown that sowing in November led to higher yields and lower insect infestation than sowing in October and December. The insecticides tested achieved a significant control of aphids and higher yields when compared with unsprayed plots. A single application of malathion or dimethoate before mid-January was recommended for chemical control.

The relative resistance of rice varieties to Maliarpha separatella was studied during 1981 and 1982 long rain seasons. The observations covered the laying of egg masses, tiller infestation, incidence of “whiteheads” and, in some cases, the grain yield.

The results indicated that the varieties BG 34™8 and BG 90™2 received the highest egg masses per plot which apparently caused “whiteheads”. The remaining 10 varieties only indicated moderate response. The 1982 long rain season under no control and carbofuran 5G application regimes showed reduced tiller infestation only in BG 90™2 and Basmati 217. The five tested varieties did not show any marked difference in tiller infestation under the two regimes. Hence, BG 90™2 and Basmati 217 showed some susceptibility of M. separatella, while the rest of the varieties remained moderately resistant.

Moth population varied according to the growth stages of the rice crop in the field, with the peak occurring during the booting to maturation stages.

Losses of stored seed to insects in the tropics have reached levels of major concern. Synthetic insecticides, while effective, are generally very expensive for small fanners. The efficacy of two plants, Hyptis spicigera and Cassia nigricans, used by farmers to control insect infestation in stored cowpeas was determined. The oviposition and hatching of bean weevils (Acanthoscelides obtectus), under controlled environmental conditions, were reduced following treatment with EtOH extracts (1 g plant material 1 ml EtOH) at low application rates with EC50 between 0.3 and 14 μl extract/g bean. Further field studies are proposed to determine if such natural products can be further exploited to reduce stored legume losses.