Cotton yield decrease in Côte d’Ivoire are important because of the climate change and pest infestations. The target of this survey is to analyze the spatio-temporal dynamics of Intra-Seasonal Descriptors (ISD) of rainfall and the annual mean infestation levels (MILs) of two pests, Helicoverpa armigera and Jacobiella facialis, as well as their interactions. The analysis datas are mainly constituted of annual rainfall and entomological data of H. armigera and J. facialis covering the period 1971-2016. The spatio-temporal distributions of rainfall ISDs and pest MILs were statistically analyzed, mapped, and their interactions determined using Instat+ and Surfer 11 software. Outcomes showed an interannual variability in rainfall ISDs, with coefficients of variation exceeding 30%. For H. armigera, MIL peaks shifted from the South and Center (1995–2000) to the Center-East and North-East (2011–2016), with an overall declining trend in MILs, attributable to the adoption of the Insecticide Resistance Management Program (IRMP) in 1999. However, a recent increase in peak levels suggests that climatic conditions particularly reduced cumulative rainfall and fewer rainy days favor its development. Regarding J. facialis, MILs increased from 3 to 16 infested plants per 30 plants, due to the IRMP’s limited focus on this pest, with the infestation hotspot shifting from the North (1995-2000) to the North-East and Center-East (2011-2016). These results demonstrated the relevance of integrating climatic conditions into pest management strategies.

Jassids are polyphage pests that occur on several host plants. These insects were minor pests on okra and eggplant in Côte d’Ivoire. However, during this season, attacks, similar to those observed on cotton for more than a decade, were reported by farmers. Their invasion on these crops has raised concerns among farmers who also grow cotton. A mission was undertaken to identify the jassid populations that had appeared on these crops. It led to the identification of three species: Jacobiasca lybica (Bergevin & Zanon, 1922), Jacobiella facialis (Dworakowska, 1972) and Amrasca biguttula (Shiraki, 1913). The most abundant species were J. lybica (49.4%) and A. biguttula (47.8%). The species J. facialis was identified only on eggplant with a proportion of 2.8 %. At least two of the species cohabit in the same field. The cohabitation of these species reflects the virulent character of the attacks. A strong outbreak was observed during the period from June to July. This study therefore provides important information for decision-making.

This study aimed to evaluate the efficacy of the biopesticide Prolaly on the improvement of productivity and quality of tomato (Solanum lycopersicum L.). The study was carried out in a randomized complete block design with three (03) repetitions. Treatments were carried out once a fortnight, using a sprayer, 21 days after transplanting (DAT). Vegetative growth parameters, statistically identical for all treatments at 32 DAT, were statistically different at 75 DAT. Phenological stages did not vary between treatments. The entomological data obtained revealed that the TB biological treatment was more effective in controlling whiteflies but less effective against Helicoverpa armigera. Furthermore, two diseases were observed in the experimental plot. They are a virus related to the spoon leaf curl virus (TYLCV) and a fungal disease related to collar rot. The incidences of virus disease on tomato plants were 80, 80 and 100% for TC, TB and T0 treatments respectively. Regarding fungal disease, the incidences were 20, 30 and 50% for TC, TB and T0 treatments, respectively. However, the highest healthy fruit rate (56.34%) was obtained with the TB treatment with a net yield (6.15 t/ha) statistically identical (p = 0.0230262) to that of the TC treatment (6.31 t/ha). Plant extract formulations would be an alternative in the biological management of diseases and insect pests of vegetable crops.

In Côte d'Ivoire, the loss of cotton yield is mainly due to attacks caused by pest insects such as, the pink worm, Pectinophora gossypiella Saunders. For decades, the repeated use of chemical insecticides to control these pests has threatened the viability of the production system. Faced with the negative consequences linked to the use of synthetic chemicals, the search for alternative methods is essential. The objective of this study is therefore to evaluate the chemical properties and the insecticidal activity of essential oils extracted from Cymbopogon citratus, Cymbopogon nardus and Citrus sp on P. gossypiella. In the laboratory, nine concentrations (0.25; 0.50; 1; 2; 4; 8; 16; 32 and 64 %) for each of the three essential oils, with three replications, were tested by topical application method on adults of the pest using a micro-applicator. Results showed that the pest developed variable levels of sensitivity to those plant oils. The one extracted from C. citratus was the most toxic to P. gossypiella. The lethal concentrations (LC50 and LC90) measured were 1.67 and 4.07 % respectively. Furthermore, the results of the gas chromatography coupled mass spectrometry (GS/SM) analysis indicated that the essential oils of the three aromatic plants evaluated were strongly composed of monoterpenes (91.57-100 %). C. citratus extract was the richest in oxygenated monoterpenes (73.71 %) followed by C. nardus extract (46.59 %). The essential oil of C. citratus can be used rationally as an alternative option to chemical in the current cotton pest control program in Côte d’Ivoire.