Susceptibility of two spotted spider mite Tetranychus urticae KOCH (Acari; Tetranychidae) to some selected miticides in the Greater Accra Region of Ghana

The two-spotted spider mite Tetranychus urticae is a serious pest of vegetables, fruits and field crops in Ghana but hardly noticed by farmers. A recent survey in parts of Greater Accra Region revealed that farmers do not specifically target T. urticae in terms of control but use insecticides at high dosages and at short intervals to address the complex of pest affecting their crops. This practice is a recipe for resistance development in mite pest. Susceptibility studies were carried out using five miticides, lambda cyhalothrin, emamectin benzoate, prosular oxymatrine, imidacloprid and sulphur. Adult T. urticae were collected from four suburbs in Accra (Opeibea, Ashaiman, University of Ghana Farm and Department of Crop Science Sinna Garden). These populations were used to raise colonies on garden egg plants in separate laboratories. Infested leaves were taken from the plants and sprayed with serial dilutions of the miticides and mortality recorded after 24 h. The LD50 values and slopes were determined using probit analysis and resistance factors calculated. All field populations were quite resistant to Karate® (up to 21.6-fold) but were susceptible to the other four products where resistance factors were quite low. The University of Ghana Farms, Sinna Garden and Ashaiman populations were susceptible to Imidacloprid except the Opeibea population which showed a low level of resistance (9-fold). Synergism assays using piperonyl butoxide (0.4 μL/mL) and Diethyl maleate (1.0 μL/mL) on the Karate®-resistant population showed that the application of these products 1 h before treatment with Karate® reduce resistance in the Opeibea population from 21-fold to between 2.9 to 4.3-fold whereas that of Ashaiman was reduced from 19-fold to 2.6-fold suggesting the involvement of glutathione-S-tranferases (GSTs) and cytochrome P450 monooxygenases and esterases as the possible mechanisms of resistance.© 2016 International Formulae Group. All rights reserved.Keywords: Tetranychus urticea, resistance, glutathione-S-tranferases, cytochrome P450 monooxygenases, esterases, piperonyl butoxide, diethyl maleate

Management of insect pest complex of cowpea (Vigna unguiculata) with phosphorous-enriched soil and aqueous neem seed extract

The study determined the major insect fauna of cowpea and evaluated the effectiveness of neem seed water extract (NSWE) and soil amendments in managing insect pest complex of cowpea at Juaboso in the Western Region. Phospho-compost was applied at the rate of 560 g plot-1 (865 kg ha-1). The NSWE was applied at the rate of 50 g 1-1 (15 kg ha-1). The phosphate rock and cymethoate were applied at the rate of 195 g plot-1 (300 kg ha-1) and 2.5 ml 1-1 (750 ml ha-1), respectively. Insect fauna belonging to eight orders were found associated with cowpea in the field. The major insect pests were Aphis craccivora (Koch), Spodoptera littoralis (F), Empoasca spp., Ootheca mutabilis (Sahlberg), Zonocerus variegatus (L.), Megalurothrips sjostedti (Trybom), Maruca vitrata (Fabricius), and Anoplocnemis curvipes (Fab.). Neem seed extract and cymethoate (synthetic insecticide) significantly reduced the incidence of these insect pests, thereby reducing the damage caused to the leaves and pods in treated plots. The incidence of beneficial insects was higher on NSWE-treated plots than on cymethoate- treated plots. These included Mantis mantis, species of Bombus, Crematogaster and Coccinella, and dragonfly. This suggests that NSWE was less harmful to beneficial insects than cymethoate. The phospho-compost-NSWE treatment recorded grain yield of 1.168 tonnes ha-1, which was 68.5 per cent higher than the no soil amendment-no insecticide treatment (0.368 tonnes ha-1). The phospho- compost-NSWE insecticide treatment had a profit margin of ¢1,804,000.00 ($212.2), whilst the no soil amendment-no insecticide treatment had a loss of ¢373,000.00 ($43.9). The use of phospho-compost and neem seed extract may represent an important component of the integrated crop and pest management strategy in traditional farming systems in Ghana.Des études étaient entreprises à Juaboso dans la région ouest du Ghana pour déterminer la faune d'insecte majeure de dolique et pour évaluer l'efficacité de l'extrait d'eau de la graine de margousier (EEGM) et d'amendements du sol dans la lutte contre l'ensemble d'insectes ravageurs de dolique. Le phospho-compost était appliqué à la proportion de 560 g lot-1 (865 kg ha-1). Le EEGM était appliqué à la proportion de 50 g l-1 (15 kg ha-1). La roche de phosphate et la cyméthoate étaient appliquées à la proportion de 195 g lot-1 (300 kg ha-1) et 2.5 ml l-1 (750 ml ha-1), respectivement. La faune d'insecte appartenant à huit ordres était trouvée d'être associé avec la dolique au champ. Les insectes ravageurs majeures étaient Aphis craccivora (Koch); Spodoptera littoralis (F), Empoasca spp., Ootheca mutabilis (Sahlberg), Zonocerus variegatus (L.), Megalurothrips sjostedti (Trybom), Maruca vitrata (Fabricius), et Anoplocnemis curvipes (Fab.). L'extrait de la graine de margousier et la cyméthoate (insecticide sythétique) provoquait une réduction considérable de la fréquence de ces insectes ravageurs avec une réduction qui en a résulté aux ravages faits aux feuilles et aux cosses dans les lots traités. La fréquence d'insectes bénéfiques était plus élevée sur les lots traités d'EEGM que sur les lots traités de cyméthoate. Parmi ceux étaient Mantis mantis, espèces de Bombus, Crematogaster, Coccinella et la libellule. Ceci suggère qu'EEGM était moins nuisible aux insectes bénéfiques que la cyméthoate. Le traitement de phosphocompost – EEGM enregistrait un rendement de grain de 1.168 tonnes ha-1 qui était 68.5 pour cent plus élevé que le traitement de sans-amendement de sol–sans-insecticide (0.368 tonnes ha-1). Le traitement de phospho compost - EEGM avait une marge bénéficiaire de 1,804,000 cedis ($212.2) alors que le traitement de sans-amendement de sol–sans-insecticide avait une perte de 373,000 cedis ($43.9). L'utilisation de phospho-compost et d'extrait de la graine de margousier pourrait représenter un élément important de la stratégie intégrée de l'amenagement de culture et de la lutte contre les ravageurs dans les systèmes d'agriculture traditionnelle au Ghana. Ghana Journal of Agricultural Science Vol. 39 (1) 2006: pp. 10

Neem as a cost-effective and potent biopesticide against the diamondback moth Plutella xylostella L. (Lepidoptera: Plutellidae) and the cabbage webworm Hellula undalis F. (Lepidoptera: Crambidae)

Cabbage is an important cash crop to the resource-poor farmers in sub-Saharan Africa and offers a good source of vitamins and minerals. The diamondback moth (DBM), Plutella xylostella L. and the cabbage webworm, Hellula undalis F. are major pests causing significant losses to brassica crops worldwide. During the major and minor seasons of 2015, an experiment was carried out at the University of Ghana Soil and Irrigation Research Centre (SIREC), Kpong to determine the effect of some pesticides (synthetic insecticides-chlorpyrifos and lambda-cyhalothrin, botanicals - hot pepper fruit extract, aqueous neem seed extract, local insecticidal soap - ‘alata samina’ and water as control) in controlling the diamondback moth and the cabbage webworm on cabbage. Cabbage seedlings were transplanted onto 3m x 3m plots, and plots were labelled by randomly assigning treatments to them. The experiment was laid out in a complete randomised block design, consisting of six treatments in three replications. Treatments were applied weekly, two weeks after transplanting and data on the population of the diamondback moth and the cabbage webworm, multiple head formation were collected weekly. At the end of each season the resulting yield was assessed for marketability, and cost benefit analysis carried out to determine the cost: benefit ratio. The results revealed that the highest population of the diamondback moth was recorded in the plots sprayed with chlorpyrifos and lambda-cyhalothrin, with neem recording the least number of diamondback moth and cabbage webworm populations. The highest marketable yield of 13.82t/ha and 28.36t/ha was recorded for the neem sprayed plots with a cost: benefit ratio of 1:48.6 and 1:137.1 for both seasons, respectively, followed by pepper extract (3.92t/ha, 1:10.5) for the major season and ‘alata samina’ (8.86t/ha, 1:36.4) for the minor season. The aqueous neem seed extract can be used by resource-poor farmers in Ghana as the most cost-effective biopesticide against the diamondback moth and the webworm on cabbage

Parasitism of Plutella xylostella (L.) (Lepidoptera: Plutellidae) Populations on Cabbage Brassica oleracea var. capitata (L.) by Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) in Ghana

The study was carried out at the Weija Irrigation Company site at Weija, in the Greater Accra Region of Ghana, to determine the seasonal abundance of the major parasitoid of Plutella xylostella (L.) populations on cabbage, Brassica oleracea var. capitata (L.) during the rainy and the dry seasons. The results indicated that Cotesia plutellae (Kurdjumov) was the most abundant and important parasitoid of P. xylostella on cabbage. It accounted for about 92% of the parasitoids, and occurred in all the three seasons of planting. The rest consisted of four facultative hyperparasitoids: Oomyzus sokolowskii, Aphanogmus reticulatus, Elasmus sp. and a Trichomalopsis sp., and two primary parasitoids, Pediobius sp. and Hockeria sp. A significantly higher rate of parasitism (68.6 ± 12.9%, P < 0.05) of P. xylostella by C. plutellae occurred during the major rainy season and the least (9.9 ± 7.1) in the minor rainy season. Cotesia plutellae acted in a density dependent manner, and its numbers increased as that of the host in all three seasons. The coefficient of correlation was highest in the major rainy season (r = 0.97) with a coefficient of determination of 0.97. In the minor rainy season r = 0.55, and in the dry season r = 0.66. The annual coefficient of correlation was r = 0.51 and the coefficient of determination = 0.262. Hence, in an annual production of cabbage, 26.2% of the variation in parasitism was due to the variation in the number of P. xylostella. The results, therefore, indicate that C. plutellae can be used in the development of an integrated pest management programme (IPMP), against P. xylostella in Ghana

Field studies on the susceptibility of six plantain cultivars to infestation by the banana weevil, Cosmopolites sordidus Germar (Coleoptera: Curculionidae) in Ghana

Field studies were used to identify plantain cultivars that were less susceptible to infestation by the banana weevil Cosmopolites sordidus Germar (Coleoptera: Curculionidae). Six plantain cultivars, Osoboaso, Borodewuio, Apantu-pa, Asamienu, Agbagba and Obino L\'Ewai, were evaluated between October 1997 and September 1998. The results indicated that all the cultivars were susceptible to weevil damage in weevil oviposition, egg hatchability, and larval growth and development. Weevil population was not significantly different among the cultivars, but differences in the corm damage were significant. Agbagba and Borodewuio were significantly more susceptible to borer attack than Obino L\'Ewai and Osoboaso, Asamienu and Apantu-pa were intermediate in their susceptibility to borer attack. Cultivating Obino L\'Ewai, Osoboaso, Asamienu and Apantu-pa, using good management practices, may increase plantain yields and enhance the sustainability of plantain production in Ghana.Cosmopolites sordidus (Germar) (Coléoptères: Curculionidés) au Ghana. Des études sur le terrain étaient faites pour identifier les variétés de plantain qui étaient moins prédisposées à l\'infestation par le charançon de banane Cosmopolites sordidus Germar. Six variétés de plantain c.-à-d., Osoboaso, Borodewuio, Apantu-pa, Asamienu, Agbagba et Obino L\'Ewai étaient évaluées entre Octobre 1997 et Septembre 1998. Les résultats indiquaient que toutes les variétés étaient prédisposées aux ravages de charançon sous l\'angle de la ponte du charançon, la capacité d\'éclore l\'oeuf, la croissance et le développement larvaire. La population de charançon n\'était pas considérablement différente parmi les variétés mais les différences entre les dégâts de bulbe étaient considérables. Agbagba et Borodewuio étaient considérablement plus prédisposées à l\'attaque d\'insecte térébrant qu\'Obino L\'Ewai et Osoboaso. Asamienu et Apantu-pa étaient intermédiaires en leur prédisposition à l\'attaque d\'insecte térébrant. La culture d\'Obino L\'Ewai, Osoboaso, Asamienu et Apantu-pa en adoptant les pratiques de bonne exploitation, peut augmenter les rendements de plantain et améliorer la durabilité de la production de plantain au Ghana. Ghana Journal of Agricultural Science Vol. 40 (2) 2008: pp. 177-18

Effect of phospho-compost on growth and yield of cowpea (Vigna unguiculata)

The effect of phospho-compost on the growth and yield of cowpea (Vigna unguiculata) was studied at Juaboso in the Western Region of Ghana. It was a factorial experiment arranged in a randomized complete block design with four replications. Phospho-compost, prepared from phosphate rock, cocoa pod husk, sawdust and poultry manure, was applied at the rate of 560 g plot-1 (875 kg ha-1) and worked into soil before planting. Phosphate rock was applied at the rate of 195 g plot-1 (300 kg ha-1) 1 week before planting. The triple superphosphate was applied as band placement of 90 g plot-1 (130 kg ha-1), 7 days after sowing. These application rates were equal to 60 kg P205 ha-1. Phospho-compost significantly (P < 0.05) increased number of leaves, number of nodules, plant biomass, number of pods per plant, and grain yield more than the control. Grain yield on the phospho-compost-treated plot was 25.8 per cent higher than the control. Phospho-compost treatment had a profit margin of ¢3,295,000.00 ($387.65). This figure compared favourably with the treatment using conventional triple superphosphate fertilizer, which recorded ¢3,422,000.00 ($402.59) profit. The controls had a profit margin of ¢2,515,000.00 ($295.88). The results of the study indicate that the use of phosphocompost (which is locally prepared) can significantly increase the yield of cowpea. Resource-poor farmers can use phospho-compost to improve the fertility of soil for higher productivity of cowpea.Une étude était entreprise à Juaboso dans la région de l'Ouest du Ghana pour faire des recherches de l'effet de phosphocompost sur la croissance et le rendement de dolique. C'était une expérience factorielle arrangée dans un dessin de bloc complet choisi au hasard avec quatre réplications. Phospho-compost, préparé de roche du phosphate, de l'écale de cosse de cacao, de sciure de bois et de fumier de volaille, étaient appliqués à raison de 560 g/lot (875 kg/ ha) et mélangés avec le sol avant la plantation. La roche du phosphate était appliquée à raison de 195 g/lot (300 kg/ha) une semaine avant la plantation. La triple superphosphate était appliquée comme un placement en bande de 90 g/lot (130 kg/ha), sept jours après les semailles. Ces taux d'application étaient équivalent à 60 kg P2 O5/ ha. Phospho-compost augmentait considérablement (P < 0.05) le nombre de feuilles, nombre de nodules, biomasse de plante, nombre de cosse par plante et le rendement de graine plus que le contrôle. Le rendement de graine sur le lot traité de phospho-compost était 25.8$387.65) et ce chiffre se comparait favorablement avec le traitement appliquant l'engrais conventionnel la triple superphosphate, qui donnait un bénéfice de ¢3,422,000.00 ($402.59). Les lots de contrôle avaient une marge bénéficiaire de ¢2,515,000.00 ($295.88). Les résultats de l'étude indiquent que l'application de phospho-compost (qui est préparé localement) peut augmenter considérablement le rendement de dolique. Les pauvres agriculteurs ingénieux peuvent appliquer phospho-compost pour améliorer la fertilité du sol pour une productivité plus élevée de dolique. Ghana Journal of Agricultural Science Vol. 40 (2) 2008: pp. 169-17

Use of the Triple-Layer Hermetic Bag against the Maize Weevil, Sitophilus Zeamais (Mots) in Three Varieties of Maize

Maize ranks with wheat and rice as one of the world’s chief grain crops. However, the safety of this important food crop is threatened by pests such as insects, rodents and moulds which results from inappropriate storage methods. Insect pest infestation accounts for about 20-50% of all food crop losses. This study was carried under ambient laboratory conditions of 32± 2oC and 72-88% r.h to determine the effectiveness of the triple-layer hermetic bag in controlling the maize weevil Sitophilus zeamais (Mot) on three varieties of maize (Obatampa, Abrodenkye and Kamangkpong). Five (5) kilograms of each variety with three replicates were infested with 50 S. zeamais and stored for three (3) months in three different types of bags (hermetic, Polypropylene and Jute). Destructive sampling was done monthly to determine the moisture content, viability of each variety and weight loss after storage. Percentage damage of grain due to S. zeamais was assessed on the different types of storage bags. The results show that the high yielding Obatampa was more susceptible to S. zeamais than the two local varieties; Abrodenkye and Kamangkpong. Damage, weight loss and germination rates were significantly (p  higher in the polypropylene and jute bags than the hermetic bags. These were also dependent on the length of storage. The triple-layer hermetic bags were effective against S. zeamais and could be used for storage of maize. Keywords: Maize weevil, Sitophilus zeamais; Triple-layer hermetic bag; Polypropylene; Jute

Spray distribution in a tree crop

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An annotated list of insects associated with citrus plantations at Kade, Ghana

(Ghana Journal of Agricultural Science, 1991-94, 24-27: 1-6