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The chemical control is the widely control method applied in Cameroon for pests and diseases by all the cocoa producers without technical suitable assistance by the State as before 1980'S. However, it is known that farmers have less knowledge on the good pesticides use for the control of a specific pest. The objective of this study was to provide insight in current pesticide use in the cocoa sector in Cameroon. A stratified sampling scheme was used. A total of 251 cocoa farmers, 20 post-harvest cocoa traders and 37 chemical retailers were randomly selected and interviewed. The study showed that 35 different chemicals were marketed in Cameroon for use in cocoa: 4 herbicides, 11 fungicides and 20 insecticides. Of 251 farmers consulted, 96.8% said that they use pesticides on their farms while 3.2% did not. Fungicides were used most often by farmers 61.8%) followed by insecticides (38.2%). Eight active ingredients although, officially banned, were still being used on cocoa farms. Over 77% of farmers do not respect the official spray recommendations for chemicals. Moreover, 64% do not respect recommended doses. Two main pesticide-supply-pathways exist in Cameroon: a legal and illegal supply chain, which provides 51% of pesticides to cocoa farmers, resulting in an estimated loss of value added tax for the Cameroonian government of about 550 000 to 2.4 million Euros per year. These results suggest that improved pests and diseases control by the State and raising farmer awareness about pesticide use in cocoa could greatly attribute to more sustainable cocoa economy in Cameroon. (Résumé d'auteur

Summary 1.Research into the successional responses of tropical forest communities following disturbance has potential applications for habitat restoration. Currently little is known of how these responses relate to the recovery of biodiversity and ecosystem processes. Succession of assemblages of decomposer arthropods is essential for the recovery of the soil community and nutrient cycling processes. 2. This study investigated the successional response of a termite assemblage to the experimental perturbation of forest habitat in southern Cameroon, examining the implications for tropical forest restoration. A randomized block design consisting of four experimental perturbations of diering severity was established in an old secondary forest in the Mbalmayo Forest Reserve. Isolated control sites were left in undisturbed forest. Recovery of the termite assemblage was assessed by measuring termite species richness and abundance at regular intervals over the subsequent 12 months. 3. The speed of recovery of the termite assemblage varied with the type and extent of perturbation. In treatments involving severe soil and canopy disturbance, termite species richness and abundance recovered more rapidly when dead wood was left on the ground following perturbation. The availability of dead wood also resulted in recolonization by a subset of the termite assemblage that was distinct compositionally from that sampled from all other treatments. This subset at sites with additional dead wood included not only certain wood-feeding species, but also soil feeders. 4. The positive eects upon the termite assemblage of leaving substantial dead wood on the ground has implications for the restoration of tropical forests following human-induced disturbances such as logging. The accelerated recovery of termite diversity and assemblage composition is a signi®cant component of soil community recovery and the restoration of nutrient cycles. These bene®ts are expected to in¯uence soil fertility and, ultimately, forest regeneration. The duration and persistence of these eects will depend crucially on the type, scale and intensity

The data revealed that rectangular traps containing pheromone blends combining both the monoester and the diester have a good potential to lure and trap adult males of S. singularis on cocoa farms. The pheromone blends used were specific for S. singularis, and the use of pheromone traps appears to be a promising strategy for incorporation into integrated pest management strategies for the monitoring or even the control of S. singularis in cocoa plantations.

Termites were sampled using randomized soil pits in 64 cropping plots, each 25 ϫ 25 m, forming an experimental agrisilvicultural system in both a 6-and an 18-year-old Terminalia ivorensis plantation, in which canopy cover, crop, cropping system and land preparation were the principal treatment variables. The treatments were established in April 1995 and sampling was carried out in A total of 82 termite species were found, of which 67 were soil-feeders. Overall termite abundance and the abundance of soil-feeders increased between November 1995 and July 1996, reaching a mean of nearly 6000 m Ϫ2 . Pooling termite data from these sampling dates, in the old plantation, the high canopy cover treatment (192 stems ha Ϫ1 ) had a greater abundance of termites, compared with the low canopy cover treatment (64 stems ha Ϫ1 ) and this effect was independent of crop type (plantain or cocoyam), cropping system (single stands or mixed crops) and land preparation (mulch retained or burned, plantain only). The young tree plantation (same tree densities as in the old plantation) showed no significant difference in termite abundance between high and low canopy (levels of tree foliage) densities, though the high canopy sheltered a greater number of termites. Analysis of covariance showed that crop yield (both plantain and cocoyam) was not directly linked to the abundance of all termite populations, but that the cocoyam yield was positively correlated with the abundance of soil-feeding termites (the majority in the assemblage) in the young plantation. This may be due to the beneficial conditioning of soil resulting from the foraging and construction activities of soil-feeders.

The effects of wet and dry seasons on soil termites within a humid tropical West African forest are examined. Samples were taken monthly, over a 14-mo period, and termite abundances and species richness were estimated. These estimates were compared with the total cumulative rainfall for 30-d, 7-d and 2-d periods before each sampling. For all these time periods abundances and species richness of termites were significantly negatively correlated with rainfall. However, the strongest correlations were generally found with the 2-d period, suggesting that short-term movement of termites up and down the soil profile may be the most important factor in the observed differences, rather than longer term changes in overall abundance or species composition. This conclusion was supported by a detrended correspondence analysis which showed no significant changes in species composition between dry and wet months.Les effets de saisons sèches ou humides, sur des termites souterrains d'une forêt tropicale humide Ouest-Africaine sont examinés. Les échantillons étaient prélevés mensuellement, sur une période de 14 mois. L'abondance en termites ainsi que leur richesse spécifique sont estimées. Ces estimations sont mises en relation avec un total cumulé des pluies d'une période de 30, 7 et 2 jours avant chaque échantillonage. Pour toutes ces durées, l'abondance et la richesse spécifique sont significativement négativement corrélées avec la pluviométrie. Toutefois, les corrélations les plus fortes sont généralement trouvées avec des pluies des 2 jours précédants, suggérant que les mouvements à court terme des termites au sein du profil du sol, seraient le facteur le plus important des differences observées, plutôt que des changements à long terme de leur abondance ou composition spécifique. Cette conclusion est confortée par une analyse des correspondances, qui ne montrent pas de changements significatifs dans la composition spécifique entre mois secs et pluvieux.

The mirid bug Sahlbergella singularis feeds on cocoa pods and shoots, causing considerable crop losses. As laboratory experimentation requires numerous insects, this study aimed at improving available rearing method of S. singularis for Cameroon. Fifty second to fifth nymphal stages were collected at a cocoa farm and reared to the adult stage on cocoa pods in an insectary (T = 24.7 AE 0.9°C, RH = 84.5 AE 6.8%, photoperiod: 12 : 12 L : D). Newly emerged females were confined for 5-6 days on cocoa twigs for sexual maturation and each female paired with a male for 24 h. The pairs were returned to the field and enclosed in mousseline sleeves on attached cocoa pods, for egg laying. After 16 days (expected egg lifetime), the sleeve cages were checked daily to detect newly hatched nymphs. Then, the pods were collected and brought to the insectary, where nymphs continued to emerge and develop into adults. Our method allowed the production of 14.6 AE 6.7 nymphs per female per generation, for 15 consecutive generations. Nymphal survival was calculated to be 68.2% and the mean duration of the nymphal development was measured at 22.7 AE 3.1 days. The rearing performance was evaluated using life-table calculations. The net reproductive rate (R 0 ) was 6.59; the intrinsic rate of increase (r) was 0.037 per female per day with a population doubling time (T d ) of 18.9 days. On average each female contributed 9.70 individuals to the population given a mean generation time (T c ) of 52.1 days. The percentage of reproductive females and the mean number of nymphs per female were significantly different between generations, with 86.8% and 18.1% in generation G7 as compared to 45.8% and 8.4% for generation G5, respectively. As rainfall showed concordant variations during the period of investigation, we discuss the impact of this factor on mirid fecundity.