Cowpea yield improvement is done by adding agricultural inputs. The use of natural substances as pesticides is being encouraged to fight against cowpea field pests. The pesticidal potentials of aqueous extracts of Azadirachta indica and Boswellia dalzielii, Metarhizium anisopliae, alone and in combination with plant extracts, as well as the commercial insecticide Decis were tested on two Vigna unguiculata varieties in field in two agroecological zones (Guinean Savanah and Sahelian Savanah) of Cameroon. The field trials were arranged in a completely randomized block design with nine treatments including control. Each treatment was replicated four times. Vigna unguiculata plants were sprayed at flowering stage thrice with insecticidal products at 5 days interval. Data assessment consisted of counting ramifications per plant, the number of pods per block, and seed yield. All the tested insecticides significantly (p<0.0001) improved the cowpea yield in the two agro-ecological zones. The productions parameters were highly influenced by variety and agroecological zone. The extracts and their combinations were as effective as synthetic pesticide (Decis). Bafia variety recorded the highest ramification rate (37.03±1.59) when treated with the combination of M. anisopliae and A. indica in Maroua (Sahelian Savanah). The same variety also produced most important pods number (90.50±16.66) in Ngaoundere (Guinean Savanah) with the combination of A. indica and B. dalzielii. The highest seed yield (44.23±2.31) was recorded in Ngaoundere with B125 variety treated with the combination of the three treatments (A. indica, B. dalzielii, M. anisopliae). A. indica, B. dalzielii, M. anisopliae and their combinations could be considered as potential natural input in the improvement of V. Unguiculata yield. This would not only increase V. unguiculata yield but also preserves environment from the pollution due to the use of synthetic residual chemicals.

In order to further clarify the growth-promoting effect of non-core Metarhizium spp. M. marquandii on plants, M. marquandii SGSF043, which was obtained from the pre-screening in the laboratory, was selected as a test strain, and the effects of the fungus fermentation broth during the stabilization period of the growth of this strain on the growth and growth of maize seeds were investigated by using fermentation broth as a submerged seed. germination, seedling growth, and inter-root soil enzyme activity of seedlings. The results are as follows: In the seed germination test, M. marquandii SGSF043 fermentation liquid had a certain inhibitory effect on the germination of maize seeds, and the 10-times dilution of the fermentation liquid significantly promoted the seed germination, and the effect was the best; After the germination test, the growth of maize germ was promoted by the treatment groups of 10 times and 1,000 times diluent; In the field plot experiment, the 100-fold dilution had the best growth promotion effect, which could promote the growth of cabbage seedlings and increase the seedling biomass. The results show that M. marquandii SGSF043 has the potential to promote the growth of maize and improve the soil environment, which provides a theoretical basis for the research and application of M. marquandii in farmland.

Spodoptera frugiperda is a significant economic pest of maize in Uganda. Many Ugandan maize farmers employ synthetic insecticides as their main form of control despite the negative impacts of these chemicals. The study aimed to determine the effect of synthetic, semi-synthetic and bio-pesticides on maize leaf damage, and abundance of S, frugiperda and its parasitoids in Wakiso and Lira districts. The experiments were laid out in an RCBD with six treatments in 2020 and nine treatments in 2021, replicated four times. The treatments with the biggest decrease in leaf damage and infestation were Amdocs and Roket®, followed by Nimbecidine. The biopesticides were not always more effective than the untreated control, though; their efficacy was often lower than that of synthetics, semi-synthetics, and botanical. We recovered one egg parasitoid, Telenomus remus, and seven egg and egg-larval parasitoids (Coccygidium luteum, Coccygidium sp., Cotesia icipe, Chelonus sp., Micranisa sp., Charops cf. diversipes, and Tachinidae sp. Among these, C. cf diversipes, Chelonus sp., C. luteum, C. icipe and Tachinidae were the most abundant. Parasitism was low, averaging 10% for eggs and 5.3% for larvae. Synthetic, the semi-synthetic and Nimbecidine often increased higher yield when compared with the untreated control. There were genrally low population of parasitoids, althoguh there were some indications of reduced population of parasitoids in plots treated with Amdocs and Roket®, while percent parasitism was not affected. In some instances, higher yields were even realized in untreated control. While considering the tactics to integrate, assessing the practices more compatible with biological practices will be necessary.

The red palm weevil (RPW) Rhynchophorus ferrugineus is highly destructive invasive pest for palms whose management is mainly by application of synthetic pesticides. Entomopathogenic fungi (EPF) have been primarily studied as a preventative control measure due to the horizontal transfer of conidia within the RPW population. We previously demonstrated the horizontal transmission of fungal conidia from an egg-laying surface to the female weevil and then to the eggs and larvae. Based on that strategy, this study aimed to evaluate the virulence of commercial EPF products and laboratory EPF preparations to RPW females and their progeny and their ability to protect palms against infestation. As such, it serves as a screening platform for field experiments. Mortality rates of females and eggs depended on the applied treatment formulation and fungal strain. Velifer®, a Beauveria bassiana product, and Metarhizium brunneum (Mb7) resulted in 60–88% female mortality. Mb7—as a conidial suspension or powder—resulted in 18–21% egg-hatching rates, approximately 3 times less than in the non-treated control. Treating palms with Mb7 significantly inhibits infestation signs and results in 75% and 100% protection, respectively. These results lay the foundation for investigating the protective rate of EPF products against RPW in date plantations.