The aim of this study was to identify and develop entomopathogenic fungi as biopesticides for management of Maruca vitrata (Fabricius). Fourteen isolates of Metarhizium anisopliae (Metchnikoff) Sorokin and six of Beauveria bassiana (Bals.-Criv.) Vuill. were screened against first instar larvae of M. vitrata. The two most virulent isolates were selected and further tested for production in four liquid media. Different formulations of one isolate were evaluated against different developmental stages. Metarhizium anisopliae ICIPE 18 and ICIPE 69 caused highest larval mortality of 91 and 81%, with lethal time to 50% mortality (LT50) values of 1.8 and 1.7 days and LC50 of 1.07 × 107 and 3.01 × 106conidia/ml, respectively. ICIPE 69 yielded more biomass and propagules in two liquid media than ICIPE 18. All developmental stages and adult moths were susceptible to fungal infection and horizontal transmission caused a significant reduction in fecundity. Isolate ICIPE 69 was identified as the most potent isolate for managing M. vitrata based on demonstrated efficacy against different developmental stages and amenability to production in liquid media and could be utilized as an alternative to pesticides in cowpea IPM.

The brown cocoa mirid, Sahlbergella singularis is the most important insect pest of cocoa for field damage has been classified into three categories that include blast, stagheadedness and mirid pocket. The mirid attack predisposes the cocoa plant to secondary infection by opportunistic pathogenic fungi. This study evaluated the dieback conditions associated with mirid damage due to associated fungi from lesions on pods, twigs and pin punctures. The relationship between Phytophthora black pod infection and mirid infestation in the field was also established. The results indicated that dieback progression from the mirid lesions (8.5 mm) was significantly different (P< 0.05) from that of pin punctures (7.8 mm). Lasiodiplodia theobromae had the highest proportion of isolates from pods (33%), twigs (47%), and pin punctures (38%). Fusarium decemcellulare (Albonectria rigidiuscula) accounted for 27.8% and 31.6% from pods and twigs; however, it was not recovered from pin punctures. Other isolated pathogens were Aspergillus species and Rhizoctonia species. There was a significantly strong positive correlation coefficient of 0.74 between the mirid population and the black pod disease infection in the field. The major fruit-bearing season of cocoa witnessed an increase in mirid infestation and blackpod infection. The effect of mirid–pathogenic fungi-associated damage could be ameliorated through effective crop husbandry practices to ensure that cocoa plant tissues are not unduly exposed to biological and mechanical injuries.

House flies (Musca domestica L.) are key pests of poultry and are managed worldwide with a variety of insecticides. However, extensive and injudicious use of insecticides has led to the development of resistance in many insect pests. Insecticide mixtures can increase the efficacy of the product and/or delay the development of resistance, thus making them a useful tool for pest control. In addition to their efficacy when used alone, mixtures of emamectin benzoate, spinosad or nitenpyram with either lambda-cyhalothrin or profenofos were assessed against a susceptible strain of house flies collected from poultry farms. The analysis revealed that combination indices for lambda-cyhalothrin/emamectin benzoate and lambda-cyhalothrin/spinosad mixtures were significantly >1, indicating an antagonistic effect. In contrast, the indices for all the tested ratios of lambda-cyhalothrin/nitenpyram were significantly < 1, suggesting a synergistic effect. For mixtures containing profenofos, combination indices varied significantly. For example, synergism was observed in a 1:1 mixture containing lambda-cyhalothrin and emamectin benzoate, but antagonism occurred when a higher proportion of the latter insecticide was used. Conversely, synergism in a mixture containing profenofos and nitenpyram was observed only when a lower proportion of the second insecticide was used. The present results suggest that ideal insecticide mixtures must be empirically determined and alternative strategies such as mosaics, rotations and cultural control should be considered for the management of the house fly.

Insect species can respond adaptively to stress temperature conditions including both thermal limits and reaction norms. In this study, we considered two populations of the whitefly Bemisia tabaci (Gennadius), in which adaptive differentiation was detected for tolerance to upper thermal limits. These two populations are found in two regions of Colombia with climatic differences: the Caribbean region with high environmental temperatures and the Southwest region with lower temperature regimens. We assessed the thermal responses to a range of 1 h heat shocks (37, 39, 41, 43 and 44 °C) performed below the thermal limits for this species. Thermal responses were measured using three life-history traits involved in fitness: survival, fecundity and viability of the offspring after heat shocks. Survival or fecundity as a response to heat shocks did not differ among populations; however, there were significantly different responses for viability between populations. The Southwestern population showed higher viability responses to low heat shocks than the Caribbean population. This relationship suggests a potential trade-off, which appears to be associated with climatic regions. In addition, these results suggest that adaptation under thermal limits does not necessarily involve similar responses throughout the reaction norm. A potential ongoing evolutionary response is taking place through the thermal reaction norms for viability after the invasion by this pest in Colombia.