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Okra, Abelmoschus esculentus (L.) Moench, is attacked by the adult chrysomelid flea beetles, Podagrica spp. Information on physiological disruptions that occur due to flea beetle infestation affecting okra yield loss is incomplete. Screenhouse and field experiments were established to examine the effects of insect populations on leaf abscission, chlorophyll concentration, and biomass partitioning. Okra plants were grown in wire mesh screen cages and artificially infested with flea beetles, P. uniforma Jac., at population densities of 0, 5, 10, 20, 30, and 40 pairs per plant at 3 weeks after sowing (1 pair = 1 male and 1 female). In both experiments, okra plants had increased leaf abscission up to 100% at the 40-pair level in response to P. uniforma-induced injury. There were no significant differences in chlorophyll concentrations of plants at 0-, 5-, and 10-pair levels of infestation, suggesting the use of a compensatory mechanism by plants; at the 20-pair level a significant reduction occurred. Number of leaves per plant, shoots, roots, and dry fruit and total dry matter yield were reduced with infestation above the 20-pair level. More biomass was partitioned into roots at the 5-and 10-pair levels, but insect damage at populations beyond these levels completely suppressed the plant's ability to partition biomass. Dry fruit yields were reduced more than 50% when beetle populations increased beyond 20 pairs in both experiments. There was a correlation between insect density and number of leaves per plant and shoot,

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Background Coptotermes sjostedti Holmgren (Isoptera:Rhinotermitidae) is one of the major termite species found infesting woods and other plant materials in Africa. Bioassays were carried out at the Arboretum of the Department of Forestry and Wildlife Resources Management, University of Calabar, Nigeria to investigate the effect of oils from the kernel of Jatropha curcas L. and Azadirachta indica oils A. Juss against the African subterranean termite (Coptotermes sjostedti Holmgren). Treatments comprised of the plant oils and Solignum (a synthetic termiticide, serving as positive control) applied at the rate of 5, 10 and 15 mL per 100 cm3 of the wood from seven plant species. Untreated woods also served as control. Seven wood species were placed in a test arena and artificially infested with 50 termites per unit. The setup was a randomized complete block design with four replicates. Data on termite mortality and wood weight loss were recorded. Results The use of 10 and 15 mL of J. curcas oil caused more than 90% mortality of C. sjostedti, after 96 h, kept wood consumption by the insect below 6.0% after 3 months, and these outcomes were similar to that of Solignum at the same concentrations. About 35.0–65.2% reduction in weight was observed among untreated woods from the tested woods, indicating their susceptibility to C. sjostedti attacks. Correlation analysis shows a significant (r > − 0.900; P < 0.0001) negative association between termite mortality and the  rate of wood consumption. Conclusion The use of J. curcas oil at 10 mL per 100 cm3 of wood could be a potent alternative to Solignum for the control of C. sjostedti.

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