Aliquots of powdered dried leaves of Tephrosia vogelii (Leguminosae – Papilionoideae) were extracted with hexane, acetone and ethanol. The extracts were tested for their potential to protect stored legume seeds from damage by the bruchids Acanthoscelides obtectus, Callosobruchus maculatus and Callosobruchus chinensis (Coleoptera – Bruchidae). While the acetone and ethanol extracts were ineffective except for a significant but low effect on A. obtectus, the hexane extract had a relatively high efficacy, providing similar control of all three bruchid species. This effect was manifested in slowly‐reduced adult survival within 7 days and in reduced numbers of eggs laid and of F1 progeny produced, resulting in seed damage averaging 7.1% compared to 99.8% in the untreated controls after one generation. These findings are discussed in the context of previously identified constituents of T. vogelii, the rotenoids rotenone, tephrosin and deguelin.

In the oil palm (Elaeis guineensis Jacq.), an active endogenous lipase is responsible for the massive release of free fatty acids (FFA) in the mesocarp of fruits at maturity. This can lead to the production of oils with unacceptable acid values. We have investigated the lipase activities in 39 genotypes of oil palm presently used in breeding programs. While most E. guineensis genotypes exhibited high lipase activity values, four of them with negligible activities were identified. We analyzed in situ lipolysis in the mesocarp upon severe wounding of fruits. The FFA content of high-lipase fruits ranged from 17 to 55%, while all low-lipase fruits contained less than 7.5% FFA. The analysis of oil from fallen overripe fruits indicated that all lowlipase genotypes contained less than 1.2% FFA (oil acidity ,5% FFA, FAO-WHO international norms), while all but one high-lipase genotypes had FFA contents much higher than the acceptable standards. Because the identified low-lipase lines are of high agronomical value and at least one of them is an elite genotype, it will soon be possible to provide farmers with new low-lipase oil palm lines allowing significant savings on labor costs, without any need for further breeding.

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Laboratory and screenhouse experiments were conducted to identify antibiosis and tolerance in four wild accessions of cowpea, Vigna unguiculata subsp. dekindtiana, to Clavigralla tomentosicollis Stål, the most damaging pod-sucking bug on cultivated Vigna genotypes in West Africa. The wild accession TVnu 151 showed antibiosis resistance, causing >50% mortality of the nymphs within 3 d of placing them on pods. Nymphs died more quickly on TVnu 151 than on TVnu 72, the wild and resistant control of the V. vexillata species which affected the weights of surviving insects to a much greater degree than TVnu 151. The three other accessions of the subspecies dekindtiana (TVnu 369, TVnu 517, and TVnu 707) did not cause significant mortality to the bugs, but rather extended their developmental time, with surviving adults showing lower weights and slower oviposition rates than those on the susceptible control IT84S-2246. Wild accessions affected male and female bugs differently, resulting in differential survival. This was reflected by the sex ratio which was male biased on the wild accessions (1:0.3-1:0.9), and female biased on IT84S-2246 (1:1.5). No evidence of tolerance was found in the four accessions of V. unguiculata subsp. dekindtiana. Overall, seed traits seemed to be the major resistance component in these wild accessions.

Several Vigna species were used to determine the role of pod trichomes and pod toughness in the resistance of cowpea to feeding damage by the coreid bug Clavigralla tomentosicollis Stal. The scanning electron microscopy study revealed the presence of glandular and non-glandular trichomes on the pod wall of all test genotypes. The cultivated genotypes TVu 1890, TVu 3354 and IT84S-2246 of the V. unguiculata ssp. unguiculata showed significantly lower (P<0.05) densities of glandular trichomes than accessions of the wild Vigna species (TVnu 72, TVnu 151, and TVnu 707). All pods were similar with respect to the density and length of non-glandular trichomes. The two wild accessions TVnu 151 and TVnu 707 of the V. unguiculata ssp. dekindtiana had low pod strength similar to that of the susceptible genotype IT84S-2246, and also showed high seed damage levels comparable to that of this susceptible genotype. These accessions of the subspecies dekindtiana contrasted with the wild and resistant accession TVnu 72 of the V. vexillata species which suffered minor seed damage in