The tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is an invasive pest that devastates the production of tomatoes and other solanaceous vegetables. Since its trans-Atlantic invasion in 2006, T. absoluta has spread and established in many countries across the Afro-Eurasian Supercontinent, causing huge yield losses. This study aimed to determine the relationship between temperature and the life history traits of T. absoluta and provide the thermal thresholds for development using life cycle modelling. Linear and non-linear models were fitted to life table data collected at five constant temperatures of 15, 20, 25, 30, and 35 °C, with Relative Humidity 70 ± 5% and photoperiod 12L:12D. Another experiment was conducted at fluctuating temperatures to validate the laboratory results. Tuta absoluta completed its life cycle at temperatures between 15 and 35 °C. The development time ranged between 4.0–11 days, 6.3–16.0 days, and 5.4–20.7 days for egg, larva, and pupa, respectively. The lowest thermal threshold was estimated at 8.10, 7.83, and 11.62 °C, respectively for egg, larva, and pupa. While the optimum temperature for T. absoluta immature stages survival and female fecundity were predicted at a temperature range of 21–23 °C. The intrinsic rate of increase (r_m), gross reproductive (GRR), and net reproductive (Ro) rates were significantly higher at temperatures between 20–25 °C. The model validation outcome showed similarities between observed and simulated values for development time, mortality rate, and life table parameters, attesting to the quality of the phenology model. Our results will help in predicting the effect of climate warming on the distribution and population dynamics of T. absoluta. Furthermore, the results could be used to develop management strategies adapted to different agroecological zones.

Associations between the South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), and its native parasitoids need to be updated to increase the implementation of pest control strategies. In this study, T. absoluta-infested tomato plants were collected from three regions in Kenya. The emerged parasitoids were identified, and their abundance was correlated with agroecological parameters, viz. cropping systems, and the abundance of the predator Nesidiocoris tenuis Reuter (Hemiptera: Miridae). The study further conducted a habitat suitability prediction for the identified parasitoids. Two parasitoid species, Bracon nigricans (Szépligeti) (Hymenoptera: Braconidae) and Stenomesius sp. near japonicus (Ashmead) (Hymenoptera: Eulophidae) emerged from T. absoluta immature stages, with parasitism rates ranging from 0 to 21% and 0 to 17% respectively. Insecticide application and open field cropping negatively influenced the parasitism by S. sp. nr japonicus. Low occurrence of N. tenuis positively affected B. nigricans parasitism. The predicted occurrence of parasitoid species indicated vast suitable areas for B. nigricans in sub-Saharan Africa, Australia, and South America. Low suitability was observed for S. sp. nr japonicus in Africa. Therefore, native parasitoids, especially B. nigricans could be considered for implementation as a biocontrol agent in the Integrated Pest Management program of T. absoluta.

The invasion of Africa by the South American leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) has caused a severe threat to the production of tomato, Solanum lycopersicum L. (Solanaceae) crops. The excessive use of pesticides for controlling this pest has increased, together with the associated environmental and human health risks. The parasitoid, Dolichogenedia gelechiidivoris Marsh. (Hymenoptera: Braconidae), has been imported into Africa for classical biological control of T. absoluta. To facilitate the mass production of the parasitoid and to predict the success under field conditions, its performance under laboratory conditions was investigated at five densities of T. absoluta larvae, viz. 20, 50, 100, 150, and 200 offered to either a single or group of mated parasitoid females. The findings revealed that D. gelechiidivoris exhibited a type II functional response. Host and parasitoid densities affected superparasitism, which was generally low, less than 5%. Parasitoid offspring emergence ranged from 8 to 39 wasps for a single foraging female, and 6-59 wasps, for a group of foraging females. The host larval densities did not affect the male: female ratio. This study showed that D. gelechiidivoris acts in a density-dependent manner. Therefore, for optimisation of the mass production of the parasitoid, the maximum number of hosts should be offered to a female. The results suggest that D. gelechiidivoris could be effective for classical biological control of T. absoluta, albeit field evaluation is required to validate this finding.

There are various postharvest treatments currently available in the market. Among these, heat-based treatments are very effective. Several hot water treatment (HWT) protocols at various temperature regimes and time durations have been developed for different mango cultivars and varieties. However, many concerns have been raised regarding the quality of fruits subjected to HWT, particularly on physical and biochemical properties. The purpose of this study was to generate empirical evidence on the effect of the HWT protocol currently recognized and accepted by the EU for Apple mango cultivar from Africa. We subjected mango to HWT at 46.1 °C for 68, 75, and 84 min and evaluated various physical and biochemical properties at 1, 3, 5, and 7 days post-treatment. Conventional methods of analysis were used to test acidity, antioxidants, minerals, nutrients, and physical properties of treated mangoes, and comparisons against untreated controls were made. We found no significant differences in pH, various acid content, total carotenoids, β-carotene content, vitamin A, aromatic volatiles, total phenolics, total antioxidant activity, various minerals, electrolytic leakage, crude protein, total carbohydrates, total sugars, crude fat, moisture content, dry matter, total soluble solids, firmness, or weight between treated and untreated mangoes. We conclude that HWT presents a viable alternative for postharvest treatment of export mangoes provided that quality attributes are maintained from preharvest, harvesting, transportation, treatment, and post-treatment handling.

BACKGROUND: Maize production in Africa is hindered by a myriad of biotic challenges, key among them being invasive and native lepidopteran stemborers. Recent invasion of the continent by fall armyworm, Spodoptera frugiperda , has further exacerbated the situation. Fortunately, Cotesia icipe was found to be very promising against S. frugiperda . However, the co‐occurrence and interaction between S. frugiperda and the stemborers ( Busseola fusca , Sesamia calamistis , and Chilo partellus ) in maize agroecosystem may jeopardize the efficiency of C. icipe as a biocontrol agent of S. frugiperda . This study investigated the performance of C. icipe on S. frugiperda , Spodoptera littoralis and the stemborers. Specifically, the preference and acceptability of C. icipe to the host insects, the physiological suitability of the hosts for its development, and the effect of these hosts on the fitness parameters of the offspring were assessed. RESULTS: Cotesia icipe accepted all the tested hosts, albeit with higher preference for Spodoptera species than for stemborers under multiple‐choice tests. Also, the highest parasitism of up to 97% was recorded on S. frugiperda compared with parasitism on the stemborers of 43% in B. fusca . Moreover, physiological suitability and fitness traits (except for per cent female offspring) varied with host species, again being optimal on Spodoptera species. CONCLUSION: Cotesia icipe demonstrated strong potential to control S. frugiperda in maize due to its high affinity for parasitization and developmental success in this host; and despite its non‐specific parasitization, the presence of other hosts may not prevent its maximum control of S. frugiperda . © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The white mango scale, Aulacaspis tubercularis Newstead (Hemiptera: Diaspididae), is one of the most destructive pests of mango worldwide. Its current management in most of the invaded areas largely depends on the intensive use of chemical insecticides. Biological control using parasitoids represents one of the most effective and environmentally sustainable management options. However, in Kenya, one of Africa's leading mango‐producing countries, no effective parasitoid species associated with A. tubercularis had previously been recorded. This study aimed to identify encyrtid parasitoids associated with A. tubercularis in Kenya, and to assess how bioclimatic factors influence their occurrence and habitat suitability. Mango leaves infested with A. tubercularis were collected from 65 mango orchards across 10 counties, with sampling sites at least 4 km apart. Newly emerged parasitoids were reared on A. tubercularis for three successive generations to confirm host suitability and successful parasitism. Morphological and molecular identification of the recovered parasitoids revealed Arrhenophagus chionaspidis Aurivillius (Hymenoptera: Encyrtidae) as the only parasitoid that parasitized the male A. tubercularis . This parasitoid species was widely distributed, occurring in 60 out of the 65 sampled orchards. Ecological niche modelling indicated that major mango‐growing areas in Kenya in the western, eastern, central, and coastal regions represent moderately to highly suitable habitats for A. chionaspidis under current and projected climatic conditions in the year 2070. The widespread occurrence and predicted persistence of A. chionaspidis highlight its potential for biological control of A. tubercularis in Kenya and other mango‐producing regions of Africa.