The aphid Pentalonia nigronervosa (Hemiptera: Aphididae) takes advantage from the quality change in banana plant associated with Banana bunchy top virus infection.

Viral diseases can change plant metabolism, with potential impacts on the quality of the plant's food supply for insect pests, including virus vectors. The banana aphid, Pentalonia nigronervosa Coquerel, is the vector of the Banana bunchy top virus (BBTV), the causal agent of Banana bunchy top disease (BBTD), the most devastating viral disease of bananas in the world. The effect of BBTV on the life-history traits and population dynamics of P. nigronervosa remains poorly understood. We therefore studied the survival rate, longevity, daily fecundity per aphid, tibia length, population growth, and winged morph production of a P. nigronervosa clone grown on healthy or infected, dessert, or plantain banana plants. We found that daily fecundity was higher on infected banana than on healthy banana plants (plantain and dessert), and on plantain than on dessert banana plants (healthy and infected). Survival and longevity were lower on infected dessert bananas than on other types of bananas. In addition, virus infection resulted in a decrease in aphid hind tibia length on both plant genotypes. The survival and fecundity table revealed that the aphid net reproduction rate (Ro) was highest on plantains (especially infected plantain), and the intrinsic growth rate (r) was highest on infected plants. Finally, the increase of aphids and alate production was faster first on infected plantain, then on healthy plantain, and lower on dessert banana (infected and uninfected). Our results reinforce the idea of indirect and plant genotype-dependent manipulation of P. nigronervosa by the BBTV.

Edible insect biodiversity and anthropo-entomophagy practices in Kalehe and Idjwi territories, D.R. Congo.

BACKGROUND: Located in the Eastern Democratic Republic of Congo (South-Kivu), Kalehe and Idjwi are two relatively unexplored territories with little to no research on edible insects even though anthropo-entomophagy practice is widespread. This study therefore aimed at exploring the biodiversity, perception, consumption, availability, host plants, harvesting techniques, and processing techniques of edible insects. METHODS: Data were collected through a field survey using three techniques, namely structured interviews, direct observations, and insect collection and taxonomy. A total of 260 respondents, 130 in each territory, were interviewed. The field survey focused on inventorying commonly edible insects as well as recording consumer preferences, preference factors, seasonal availability, host plants, harvesting techniques, and processing and preservation methods. Samples for taxonomic characterization were preserved in 70% alcohol. RESULTS: Nine edible insects, namely Ruspolia differens Serville 1838, Gryllotalpa Africana Palisot de Beauvois 1805, Locusta migratoria Linnaeus 1758, Macrotermes subhyalinus Rambur 1842, Gnathocera trivittata Swederus 1787, Rhynchophorus phoenicis Fabricius 1801, Vespula spp. Linnaeus 1758, Apis mellifera Linnaeus 1758, and Imbrasia oyemensis Rougeot 1955, were recorded as being consumed either as larvae, pupae, and adults. Ruspolia differens and M. subhyalinus were reported as the most preferred by consumers in the studied territories. A scatter plot of matrices and Pearson's correlations showed a negative correlation between preference based on taste, size, and shape, as well as perceived nutritional value. Their seasonal availability differs from one species to another and correlated with host plants availability. Harvesting techniques and processing and preservation methods depend on species, local knowledge, and practices. CONCLUSION: The huge edible insect diversity observed in Kalehe and Idjwi is evidence of anthropo-entomophagy practices in the area. In addition to being an important delicacy and traditional foods, edible insects can contribute to food, environmental, and financial security through local business opportunities. Households can rely on edible insects to meet their nutritional needs instead of conventional livestock. Indigenous practices and technologies used for harvesting, processing, and preserving edible insects must be improved to meet international standards to increase the market and capitalize on the economic potential of edible insects.

Inventory reveals wide biodiversity of edible insects in the Eastern Democratic Republic of Congo.

In response to growing food demand, edible insects are perceived as an opportunity to alleviate food insecurity. With its wide edible insects' biodiversity, the Democratic Republic of Congo is one of Africa's most critical entomophagous. This study aimed at giving a first insight on inventory showing diversity, perception, consumption, availability, host plants, harvesting techniques and processing techniques of edible insects in South-Kivu, DRC. It recorded twenty-three edible insects belonging to nine families and five orders, some of which are consumed in the larval, adult, egg and pupa stages. Rhyncophorus phoenicis, Alphitobius diaperinus, Macrotermes subhyalinus and Acheta domesticus were the most preferred edible insects in Fizi Territory, Ruspolia differens and Apis mellifera larvae in Kabare Territory, Imbrasia oyemensis, Imbrasia epimethea, Rhynchophorus ferrugineus and Rhyncophorus phoenicis in Mwenga Territory, Ruspolia differens, Macrotermes subhyalinus, Gryllotalpa africana, Nsike, Nomadacris septemfasciata and A. mellifera larvae in Walungu Territory. Ruspolia differens, I. oyemensis, A. mellifera larvae, G. africana and Nsike, were preferred for their taste. Acheta domesticus, A. diaperinus and A. mellifera larvae were abundant throughout the year, while others were only available for 9 months or less per year. Numerous plants have been recorded as their hosts, including plants used for food and income. Harvesting strategies and period, processing methods and preservation techniques depend on insect species, local knowledge and practices. These findings suggest similar and thorough studies on entomophagy across the country while encouraging the rearing of edible insects to address their existing high demand and environmental concerns.

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.

Efficacy of Metarhizium anisopliae in controlling the two-spotted spider mite Tetranychus urticae on common bean in screenhouse and field experiments.

The efficacy of aqueous and emulsifiable formulations of the fungus Metarhizium anisopliae isolate ICIPE78 was evaluated on the population density of Tetranychus urticae infesting common bean plants under screenhouse and field conditions. Synthetic acaricide abamectin was included as a check. Bean plants were artificially infested with T. urticae and allowed to multiply. Three treatments were applied in the screenhouse and 1 treatment in field trials. Mite density was recorded 2 d before spraying and weekly postspraying. The number of pods per plant, number of seeds per pod, and the dry weight of seeds per plant were recorded only in the screenhouse trials. In both screenhouse and field trials, fungal formulations applied at the concentration of 10(8) conidia/mL and the acaricide reduced the population density of mites as compared to the controls. There were significant differences in T. urticae population densities between the treatments at the various post-spraying sampling dates. In the screenhouse, the mite densities were near zero from 3-week postspraying in the treated leaves. At 4-week postspraying, there were no more leaves in the untreated control (T1) and in the control water + Silwet-L77 (T2). Fungal formulations were as effective as abamectin in reducing mite densities in both screenhouse and field experiments. There were significant differences in the production parameters during the 2 screenhouse trials, with fungal and abamectin treatments generally having the highest yield. Results of this study underline the potential of the M. anisopliae isolate ICIPE78 as an alternative to acaricides for T. urticae management.

Influence of temperature on virulence of fungal isolates of Metarhizium anisopliae and Beauveria bassiana to the two-spotted spider mite Tetranychus urticae.

Twenty-three isolates of Metarhizium anisopliae (Metschnikoff) Sokorin and three isolates of Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales: Clavicipitaceae) were assessed for their virulence against the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Based on the screening results, nine isolates of M. anisopliae and two isolates of B. bassiana were tested for their virulence against young adult (1- to 2-day-old) female T. urticae at constant temperatures of 20, 25, 30 and 35 degrees C. At all temperatures tested, all the fungal isolates were pathogenic to T. urticae but mortality varied with isolates and temperatures. Fungal isolates were more virulent at 25, 30 and 35 degrees C than at 20 degrees C. The lethal time to 50% mortality (LT(50)) and lethal time to 90% mortality (LT(90)) values decreased with increased temperature. There were no significant differences in virulence between fungal isolates at 30 and 35 degrees C; however, significant differences were observed at 20 and 25 degrees C.

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.