Feeding deterrency tests by leaf disc dipping method revealed AZT-VR/K extract of azadirachtin as the most potent antifeedant against cabbage butterfly, Pieris brassicae L. larvae. The leaf damage on treatment with the extract (at 3, 2 and 1%) was minimum and ranged between 4.9 and 16.3 % as compared to 98 % in untreated check. High level of feeding deterrency was exhibited at all the concentrations of AZT-VR/K, while in neemark (at 1%) and neem oil (at 2 and 1%), the deterrent effects declined considerably on their decreased concentrations.

An emulsion concentrate (locust lotion) containing 20% v/v neem oil and 40% w/v aqueous extract of Tetrapleura tetraptera L. was found to be most stable when subjected to viscoslty measurement, creaming rate determination, droplet size analysis and accelerated stability tests. The emulsion supported the growth of microorganisms which was prevented by a combination of 0.2% w/v methylparaben and 0.1% w/v propylparaben. Octylgallate, 0.1% w/v was added as an antioxkiant to prevent the oxidation of neem oil in the locust lotion concentrate. The recommended use concentration for protection ot cassava Manihotesculenta Crantz from damage by grasshopper Zonocerus variegatus L. was 1.8–2.2%. At 2.5%, locust lotion was phytotoxic to cassava.

Neem oil (NO), and different formulations of neem oil in a solution of Tetrapleura tetraptera as emulsifier, including neem oil emulsifiable concentrate (NOEC), neem oil slurry emulsifiable concentrate (NOSEC) and 5% NOEC obtained from the seeds of the neem plant, were tested for their efficacy in the control of Maruca testulalis Geyer, under laboratory conditions using flowers of Ife Brown, cowpea variety.

The different concentrations of NOEC (5, 10 and 20%) exhibited a high degree of insecticidal activity on M. testulalis larvae. All the treated flowers were protected from larval damage 2 days after treatment as compared to the 100% damage recorded on untreated flowers and on the flowers treated with T. tetraptera solution alone.

The NOSEC and the 5% NOEC prepared using different volumes of the emulsifier also exhibited some insecticidal activity which decreased with a decrease in concentration. NO/NOEC were superior to NOSEC and the 5% NOEC prepared in different volumes of the emulsifier.