In vitro Evaluation of PHYTOSANEB-020, A Biopesticide for the Control of Mealybug (Planococcus ficus) on Rosa multiflora and Bougainvillea spectabilis in Kimwenza-Mission

This study focused on the in vitro evaluation of the effectiveness of Phytosaneb-020, a bio-pesticide on Mealybug Planococcus ficus (Signoret) which infests Rosa multiflora (Rosa polyantha) and Bougainvillea spectabilis. Three treatments were used: Phytosaneb-020, Pacha a chemical insecticide and aqueous solution (distilled water) as a negative control. A volume of 1.5 mL for an area of ​​56.72 cm2 corresponding to the area of ​​a Petri dish, used for each treatment. Populations of Maconellicoccus hirsutus were carefully collected from bougainvillea leaves and roses. Pacha gave the highest mortality percentage for direct toxicity by contact (98.3± 2.89%) followed by Saneb-020 (93.3 ± 7.64%). The negative control, distilled water, was not effective against the insects. No death was observed (0%). The repellency effect assay revealed a repellent activity of 80% ± 20 for Saneb-20. Distilled water gave the best avoidance effect (86.7±11.6%) pointing out the fact that Mealybug Planococcus ficus doesn’t support the presence of water. Pasha exhibited low repellency effect on Mealybug Planococcus ficus (46.7±41.6%). Further investigations on different pests are strongly suggested and encouraged to improve the effectiveness of this biopesticide.

Mealybug (Hemiptera: Pseudococcidae) Species Associated with Cacao Mild Mosaic Virus and Evidence of Virus Acquisition

Theobroma cacao is affected by viruses on every continent where the crop is cultivated, with the most well-known ones belonging to the Badnavirus genus. One of these, cacao mild mosaic virus (CaMMV), is present in the Americas, and is transmitted by several species of Pseudococcidae (mealybugs). To determine which species are associated with virus-affected cacao plants in North America, and to assess their potential as vectors, mealybugs (n = 166) were collected from infected trees in Florida, and identified using COI, ITS2, and 28S markers. The species present were Pseudococcus jackbeardsleyi (38%; n = 63), Maconellicoccus hirsutus (34.3%; n = 57), Pseudococcus comstocki (15.7%; n = 26), and Ferrisia virgata (12%; n = 20). Virus acquisition was assessed by testing mealybug DNA (0.8 ng) using a nested PCR that amplified a 500 bp fragment of the movement protein–coat protein region of CaMMV. Virus sequences were obtained from 34.6 to 43.1% of the insects tested; however, acquisition did not differ among species, X2 (3, N = 166) = 0.56, p < 0.91. This study identified two new mealybug species, P. jackbeardsleyi and M. hirsutus, as potential vectors of CaMMV. This information is essential for understanding the infection cycle of CaMMV and developing effective management strategies.

COMPARATIVE BIOLOGY AND PREDATORY POTENTIAL OF Cryptolaemus montrouzieri ON MEALYBUGS

Comparative biology of Cryptolaemus montrouzieri on Maconellicoccus hirsutus and Pseudococcus citri revealed that it had completed its life cycle successfully on both species. The mean total developmental period (egg to pupa) was 18.1 days, when reared on P. citri and it was 20.9 days in M. hirsutus. The adults developed on P. citri had high fecundity 284.2 eggs / female and longevity 47.0 days than those developed on M. hirsutus. Analysis on the growth indices of C. montrouzieri showed more preference on P. citri with high suitability index of 2.51 than M. hirsutus (1.78). Among two life stages, adults of C. montrouzieri was more voracious and each adult consumed an average 258.7, 352.1 and 217.3 numbers on M. hirsutus while, it was 323.8, 715.6 and 328.6 number of eggs, nymphs and adults for P. citri, respectively. The grubs required 221.1, 55.1 and 36.6 numbers of M. hirsutus and 1079.0, 341.3 and 41.0 number of eggs, nymphs and adults of P. citri, respectively to complete life stages. Out of different instars of C. montrouzieri, third and fourth instars required around 92.1, 78.5 and 85.9 per cent and 88.9, 93.5 and 79.0 per cent of total eggs, nymphs and adults of P. citri and M. hirsutus consumed, respectively.

Management of the grape mealy bug, Maconellicoccus hirsutus (Green), using entomopathogenic fungi and botanical oils: a laboratory study

Background Laboratory experiments were conducted to evaluate the bio-efficacy and cumulative effect of entomopathogenic fungi (EPF), viz., Lecanicillium lecanii (Zimmermann) Zare and Gams, and Beauveria bassiana (Balsamo) Vuillemin and different botanical oils against grape mealy bug, Maconellicoccus hirsutus (Green). M. hirsutus infestation during berry formation has left no option other than chemical management. However, the pesticide application during this stage leads to residues. Thus, safer and sustainable biological need was tested for their effectiveness against M. hirsutus. Results Dipping bioassay technique was used to determine the cumulative mortality. When L. lecanii was used as sole (at 6 and 4 g/l), significant mortality was observed (51.63 and 50.18%). However, the maximum cumulative nymphal mortality was achieved when the combination of EPF formulations was used, i.e., 57.64% with B. bassiana + L. lecanii (6 g/l + 6 g/l). Their effectiveness was at par with the same combination but with minimal concentration, i.e., 4 g/l + 4 g/l (56.29%). Concerning the botanical oils evaluated, neem oil at 15 ml/l achieved a higher mortality of 81.36%. Consecutive effective treatment was a combination of neem oil and pongamia oil (at 10 + 10 ml/l) with 79.65% mortality. However, the standard dosage of neem oil (at 10 ml/l) and IIHR neem soap (at 10 g/l) also recorded the significant mortality of 78.09 and 77.67%, respectively. When compared, the neem oil was found significantly superior in sole and compatible combination than pongamia oil. Conclusions Lecanicillium lecanii and neem oil (sole and in combination with other compatible bioagents) proved significantly better for the management against M. hirsutus with an efficacy of 90.21 and 96.67 % mortality, respectively against the standard chemical control (more than 97%).

Identification of mealybugs, soft scale insects and their predators in vineyards across the savannah agro-ecological region of Nigeria

Insect-vectored viruses are a major threat to grapevine production but there is a dearth of information on the occurrence and distribution of key grapevine pests in Nigeria. The recent detection of grapevine leafroll associated virus-1 (GLRaV-1), a known insect-vectored ampelovirus, in Nigeria elevates the importance of the identification of its potential vectors as a precursor to assessing the risk of grapevine leafroll disease spread. This study was conducted to determine the occurrence and diversity of potential vectors of grapevine viruses and their natural enemies in vineyards across the savannah agro-ecological region of Nigeria. Forty vineyard and nursery locations were surveyed during 2016 and 45 arthropod samples were collected. The samples were first morphologically identified, and DNA barcoding was conducted on a subset of 16 representative samples using universal primers specific to the Mitochondrial Cytochrome Oxidase subunit I (mtCOI) gene of most insects. The results indicated the presence of two species of scale insects (Parasaissetia nigra and Saissetia coffeae) and two mealybug species (Maconellicoccus hirsutus and Ferrisia virgata), some ofwhich are potential grapevine virus vectors, in Nigerian vineyards. In addition, the natural enemies of these insect species were detected which includes three species of parasitoids (Anagyrus kamali, Anagyrus pseudococci and Encarsia inaron) and one predator (Hyperaspidius mimus). While the detection of mealybugs and scale insects underscore the risk of vector-mediated virus spread in Nigerian vineyards, the identification of their natural enemies indicates presence of natural biological control agents to facilitate an integrated management of economically important grapevine virus diseases in the country. Keywords: Mealybugs; scale insects; parasitoids and predators; insect vectors; grapevine viruses.

Toxicity of Jatropha and Neem Oil Combination on Pink Hibiscus Mealybug

Maconellicoccus hirsutus (pink hibiscus mealybug) is a polyphagous pest species reported in about 350 species of host plants worldwide. The chemical control method is still the most used for the control of agricultural pests. In view of this, we aim to evaluate the potential of the concentration of oils extracted from the species Azadirachta indica (Neem) and Jatropha curcas (Jatropha) on M. hirsutus, aiming at a management alternative for the pest. The experiments were carried out in air-conditioned chambers at a temperature of 25 ± 1ºC, relative humidity of 70 ± 10% and a photophase of 12h. The concentration 3% (v v-1) (defined in preliminary dilution tests) was used in the tests, with 11 interaction ratios between the oils. Mortality was assessed daily up to 72 hours after spraying. The application was carried out in two ways: indirect - on the food and walking surface; and direct - about insects. The indirect application caused higher levels of mortality in relation to the direct application. However, there was no significant difference between the concentrations for the indirect application. In the form of direct application, the combination of 60:40% neem oil and jatropha oil was the treatment that provided the highest mortality of the M. hirsutus (86.21%). The combinations between neem and jatropha oils demonstrated the potential to control M. hirsutus in both routes of application, being an alternative for the management of this pest.