A survey on the geographical distribution of Chnootriba similis (Thunberg), formerly known as Epilachna similis, was undertaken from 2001 to 2003 in the main cereal-growing areas of Ethiopia. The population density of the insect was estimated by sweep netting (100 sweeps/farm). In addition, more detailed studies on seasonal and annual fluctuations in population density of C. similis were carried out in southern Ethiopia between 2002 and 2003 by sampling 10 quadrants of 0.25 m2 per farmer's field. The damage levels were determined using scores of 0–9. The survey revealed that C. similis is widely distributed in different parts of the cereal-growing regions of Ethiopia. It was observed that the beetles had spread to altitudes ranging from 1217 to around 3000 m asl. However, the variations in population densities of C. similis cannot be directly attributed to altitude, as highly differing population densities in similar altitudes of different locations were recorded. Annual and seasonal variations in population density were observed in different areas of the southern part of Ethiopia. These results suggest that C. similis has a sporadic nature and can occasionally build up to outbreak levels. Beetles fed on both cereals (barley, wheat, tef, maize, sorghum and finger millet) and wild grasses (Leersia hexandra (Sw.), Avena abyssinica (Hoechst) and Lolium temulentum (L.)). Population densities and damage levels on the cereal crops varied considerably with the highest densities and damage levels on barley.

The recent development of geographic information systems (GIS) provides new avenues for analysing spatial patterns in insect populations. Field survey data, along with GIS and statistical models were used to predict the distribution of Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) and Cotesia flavipes Cameron (Hymenoptera: Braconidae) in Ethiopia. The results obtained suggested that the distributions of Ch. partelhis and Co. flavipes were affected by rainfall and temperature. The predicted distributions of Ch. partellus and Co. flavipes were similar. Validation of predicted values is discussed.

Surveys were conducted to determine the species composition of stemborers and their natural enemies in maize and sorghum in 1999 and 2000 in eastern, northern, southern and western Ethiopia. The six species of stemborers found attacking maize and sorghum were Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), Busseola fusca Fuller, Sesamia calamistis Hampson (Lepidoptera: Noctuidae), S. nonagrioides botanephaga Tarns & Bowden (Lepidoptera: Noctuidae), Rhynchaenus niger (Horn) (Coleoptera: Rhynchophoridae) and Pissodes dubious (Ström) (Coleoptera: Rhynchophoridae). Twenty species of primary parasitoids of eggs, larvae and pupae of Ch. partellus, B. fusca and S. calamistis were recorded. Other natural enemies, including predators, fungi and nematodes, were also found. Cotesia flavipes Cameron (Hymenoptera: Braconidae) was the dominant and the most widely distributed parasitoid of stemborers in Ethiopia, and was reared from field-collected Ch. partellus, B. fusca and S. calamistis.

Indoor-resting blood-fed Anopheles gambicie s.l. were collected from selected localities in Ethiopia. Anopheles arabiensis was the only sibling species identified. Paracentric chromosomal inversion polymorphisms were observed on the 2R and 3R arms. A significant excess of heterozygotes was obtained in samples from Siile carrying the 3Ra inversion. Similarly, significant variation was seen in the frequencies of the 3Ra inversion between the study localities. The observed intraspecific inversion polymorphisms relative to indoor resting behaviour are discussed.

Studies on the population dynamics and species composition of the sorghum stemborers Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), Busseola fusca (Fuller) (Lepidoptera: Noctuidae) and Sesamia sp. were conducted at Melkassa, Rift Valley of Ethiopia, during the 1990 and 1992 cropping seasons. Chilo partellus at 92% dominated the species composition. Busseola frisca made up 7.7% and Sesamia calamistis less than 1% of the borers. Occurrence of partellus declined with delay in planting until the third planting ( early June to early July) then increased during late planting in July. Busseola fusca alone, however, tended to increase in numbers with delay in planting. In Melkassa area, early planting in July could be considered as the most suitable, with low borer numbers, damage symptoms and resulting in fewer stalks with peduncle damage. Grain yield was also higher during early planting in July while the lowest yield was obtained during late planting in July. Weather factors showed no consistency but relative humidity seemed to have a significantly negative correlation with insect numbers in the last two plantings in 1992.

At Alemaya in eastern Ethiopia, tef (Eragrostis tef) was found to be attacked by a complex of seven shootfly species, five species belonging to the family Chloropidae and two to Muscidae. Atherigona hyalinipennis (Diptera: Muscidae) was economically the most important species in the shootfly complex of the crop. It caused 42–58% damage to growing panicles in different varieties of tef, which resulted in an estimated loss of 378–522 kg/ha. The average incubation period of eggs, developmental periods of larvae and pupae of A. hyalinipennis were 3.0, 12.7 and 9.6 days respectively, and the total life cycle was completed in less than a month in the laboratory. Larval parasitism by Neotrichoporoides nyemitawus ranged from 6.7 to 18.5%. Peak activity of A. hyalinipennis in the region was in August to September.