Bioclimatic zonation and potential distribution of Spodoptera frugiperda (Lepidoptera: Noctuidae) in South Kivu Province, DR Congo.

BACKGROUND: The fall Armyworm (FAW) Spodoptera frugiperda (JE Smith), is currently a devastating pest throughout the world due to its dispersal capacity and voracious feeding behaviour on several crops. A MaxEnt species distributions model (SDM) was developed based on collected FAW occurrence and environmental data's. Bioclimatic zones were identified and the potential distribution of FAW in South Kivu, eastern DR Congo, was predicted. RESULTS: Mean annual temperature (bio1), annual rainfall (bio12), temperature seasonality (bio4) and longest dry season duration (llds) mainly affected the FAW potential distribution. The average area under the curve value of the model was 0.827 demonstrating the model efficient accuracy. According to Jackknife test of variable importance, the annual rainfall was found to correspond to the highest gain when used in isolation. FAWs' suitable areas where this pest is likely to be present in South Kivu province are divided into two corridors. The Eastern corridor covering the Eastern areas of Kalehe, Kabare, Walungu, Uvira and Fizi territories and the Western corridor covering the Western areas of Kalehe, Kabare, Walungu and Mwenga. CONCLUSIONS: This research provides important information on the distribution of FAW and bioclimatic zones in South Kivu. Given the rapid spread of the insect and the climatic variability observed in the region that favor its development and dispersal, it would be planned in the future to develop a monitoring system and effective management strategies to limit it spread and crop damage.

The value chain of the edible caterpillar Elaphrodes lactea Gaede (Lepidoptera: Notodontidae) in the Miombo forest of the Democratic Republic of the Congo.

BACKGROUND: Elaphrodes lactea Gaede is a highly praised edible lepidopteran insect in the Miombo forest in the DRC. Both caterpillars and pupae of this species are consumed. Following recent declines in the Miombo forest, it is crucial to investigate the rate of consumption, biological, and exploitation cycles, as well as the trade and profitability of E. lactea to develop a sustainable program for its use. METHODS: We, therefore, embarked on a survey in 10 sites located in Lubumbashi between 2011 and 2015. Information on E. lactea supply chain and harvesting period was also documented as well as the mode of selling, pricing, and other determinants of the business. Data were analyzed using R2.15.0 software and means were compared using the Fisher LSD test. RESULTS: The study revealed that E. lactea is the most preferred caterpillar and several indicators guide its exploitation. Caterpillars are available between March and April, and pupation starts in May. Harvesting starts within the household surroundings before reaching the bush, and several harvesting techniques are used. The indirect mode of trade of E. lactea is the most commonly used, with the average price/kg varying between USD2.32 (during in-season = production period for caterpillars) and USD5.24 (during dry season = off-season, mainly pupae). During the peak season of caterpillar production, the harvester's average income per day varies between USD1.6 and USD3.0 whereas it varies between USD2.2 and USD5.2 during the pupal season. Anthropogenic activities, coupled with climatic factors, constitute the main drivers affecting the availability of E. lactea. CONCLUSIONS: The study, therefore, calls on a concerted action from all stakeholders to increase awareness and the development of innovative measures for sustainable exploitation of this insect while ensuring rehabilitation of the forest through community participation.

Role of entomopathogenic fungi in the control of Tetranychus evansi and Tetranychus urticae (Acari: Tetranychidae), pests of horticultural crops.

The spider mites Tetranychus urticae Koch and Tetranychus evansi Baker and Pritchard are important pests of horticultural crops. They are infected by entomopathogenic fungi naturally or experimentally. Fungal pathogens known to cause high infection in spider mite populations belong to the order Entomophthorales and include Neozygites spp. Studies are being carried out to develop some of these fungi as mycoacaricides, as stand-alone control measures in an inundative strategy to replace the synthetic acaricides currently in use or as a component of integrated mite management. Although emphasis has been put on inundative releases, entomopathogenic fungi can also be used in classical, conservation and augmentative biological control. Permanent establishment of an exotic agent in a new area of introduction may be possible in the case of spider mites. Conservation biological control can be achieved by identifying strategies to promote any natural enemies already present within crop ecosystems, based on a thorough understanding of their biology, ecology and behaviour. Further research should focus on development of efficient mass production systems, formulation, and delivery systems of fungal pathogens.

Effect of temperature on virulence of Beauveria bassiana and Metarhizium anisopliae isolates to Tetranychus evansi.

The virulence of three isolates of Beauveria bassiana (Bals.) Vuill. and 23 isolates of Metarhizium anisopliae (Metschnik.) Sorok. (Ascomycota: Hypocreales) against the tomato spider mite, Tetranychus evansi Baker and Pritchard (Acari: Tetranychidae), was assessed in the laboratory. The effect of temperature on germination, radial growth and virulence of selected isolates (two isolates of B. bassiana and nine of M. anisopliae) on T. evansi was also investigated in the laboratory. All the fungal isolates tested were pathogenic to the adult females of T. evansi, and there were significant differences in mortality between fungal isolates. The lethal time to 50% mortality (LT(50)) values ranged from 4.2 to 8.1 days and the LT(90) values from 5.6 to 15.1 days. Temperature had significant effects on germination, radial growth and virulence of the various isolates. The best fungal germination was observed at 25 and 30 degrees C, while for the fungal radial growth it was 30 degrees C. All the isolates germinated and grew at all temperatures, but germination and radial growth varied with isolate and temperature. The selected isolates were all virulent to T. evansi, but virulence varied also with isolate and temperature.