The beetle Caryedon serratus Olivier is a major insect pest responsible for the infestation and damage on groundnut during storage. To understand the infestation mechanism of groundnut stocks, studies have been carried out on this insect biology under laboratory conditions in relation with its host plants. The results have demonstrated that the pre-oviposition on groundnut lasts on average 1.28 days. The oviposition period is 12.04 days, during which 80.42 eggs on average are laid. From hatching to adult stage, C. serratus larvae development goes through four stages with variable durations according to the stage. Three families of host plants (Papilionaceae; Caesalpiniaceae and Mimosaceae) were selected for females C. serratus to lay on their seeds. The results showed that more eggs were laid on the seeds of Papilionaceae (98.75% of infested seeds) followed by Caesalpiniaceae (28.59% of infested seeds). Studies were carried out on the laying behavior of C. serratus under laboratory conditions and have revealed that whatever the conditions, C. serratus females lay on all the plant species seeds exposed. Insects' development duration has varied according to the plant species seeds used.

Phonoctonus lutescens which is a predator of Dysdercus voëlkeri (Schmidt, 1932) is present in cotton fields at the same time as its prey, D. voëlkeri. The objective of this study was to see which of the biological control or chemical control programs spares and maintains the potentially beneficial insects, especially P. lutescens. This study was conducted at three sites: Farako Bâ site located in the southern Sudanian zone and has geographical coordinates between 04˚20' West and 11˚06' North. The site of Kombissiri with 12'04'' North and 1'20'' West as geographical coordinates. The site of Kouaré with the following coordinates: 11'56'' North and 0'17'' East. The design was a 2000 m 2 paired trial subdivided into 3 subplots of 640 m 2 on the three sites. The sample area is repeated 4 times in each plot. All data were subjected to analysis of variance (ANOVA) using SPSS software (version 22.0; SPSS Inc., Chicago, IL, Usa). When significance occurred, means were separated by Bonferroni test (p < 0.05). All data were presented as the mean ± standard errors with 3 replications. For insect pests, conventional cotton was more affected by whitefly with 0.42 ± 1.10 and organic cotton by jassids with 0.75 ± 1.66 at Farako bâ. The untreated plot was significantly less infested at Kombissiri with 0.25 ± 1.38 Dysdercus voëlkeri than at the other sites. In Fada, the organic cotton was more infested by whitefly larvae and jassid flies, with respectively 0.73 ± 2.25 and 0.22 ± 0.54 plants attacked on average.