Intensive surveys conducted at Samaru and its environs in the northern Guinea Savanna of Nigeria between October 2000 and September 2002, indicated that Bemisia tabaci (Genn.) infests forty two (thirty three cultivated and seven wild) species of plants. Twenty nine of the plants were found in upland, two in the lowland and eleven in both upland and lowland (fadama) areas. Heavily infested plants were distorted, chlorotic and stunted. Symptoms of virus infection were associated with some of the infested plants. This is the first comprehensive report of hosts of B. tabaci in Nigeria.

The normal formulation of etofenprox was developed to nanoformulation and used against the adults of silver whitefly, Bemisia tabaci in eggplant fields. Three concentrations of both the normal and nanoformulations were used. The concentrations of etofenprox nanoformulation were one-fifth of the normal formulation. The nanosize of etofenprox ranged from 225 to 489 nm. The loading capacity of etofenprox was 60.7 ± 5.7%. The obtained results showed that the LC ₅₀ of the normal formulation was four times more than the nanoformulation. The LC ₅₀ for the nanoformulation was 0.9 and 3.5 ppm for the normal formulation of etofenprox. This means that the nanoformulation of etofenprox was more effective than the normal. The residues of both nano and normal formulations were determined in eggplant fruits after three applications. The obtained results showed that the residue of nanoformulation after 1 hour of treatment was 0.51 ± 0.03 compared with 0.62 ± 0.03 mg · kg ^–1 ± SD in normal formulation. After 1 hour of treatment the residue of etofenprox was reduced to 0.11 ± 0.1 and 0.22 ± 0.02 mg · kg ^–1 ± SD in nano and normal formulations, respectively. The dissipation rates of both nano and normal formulations after 1 hour were 78.3 and 64.5%, respectively. The degradation rate (K) in nanoformulation and normal etofenprox was 1.33 and 0.73 mg · kg ^–1 ± SD, respectively. The residue half-life (LR ₅₀) was 0.52 and 1 day, respectively. The preharvest interval (PHI) was 6 days for both nano and normal etofenprox formulations. The results confirmed that nanoetofenprox was more effective against B. tabaci adults, with lower persistence and lower residue than the normal formulation of etofenprox.

The tomato yellow leaf curl virus infecting tomato plants in Tanzania is reported to be different from the Old World geminiviruses. A study was initiated to investigate the transmission properties of the virus such as, acquisition feeding time, inoculation feeding time, persistence of virus in the vector, mechanical inoculation, seed and graft transmission. Results obtained indicate that the virus is transmitted persistently by Bemisia tabaci Genn., but neither mechanically – nor seed-transmissible. Minimum acquisition and inoculation time was 30 minutes. It is concluded that the properties of the agent causing the yellow leaf curl symptoms in tomato plants from different regions of Tanzania are similar and mimic those of tomato yellow leaf curl Begomovirus species studied elsewhere.