Abstract Aedes aegypti (L.) (Diptera: Culicidae) is a diurnal feeder that lives in close association with human populations. It is the principal vector of yellow fever, dengue fever and the Zika Virus. Issues of arboviral diseases have been on the ascendency in most countries including Ghana where Aedes mosquito is the main vector of yellow fever. A comparative study of the biting behavior of Ae. aegypti and the identification of subspecies were undertaken using molecular technique. Standard human landing technique was used to collect both indoor and outdoor biting mosquitoes at three zones located in the Upper East (Bolgatanga), Upper West (Nadowli), and Northern (Damongo) Regions of Ghana during the dry and rainy seasons between 0600 and 1800 Greenwich Mean Time (GMT). All collected mosquitoes were identified morphologically using taxonomic keys. random amplified polymorphic DNA polymerase chain reaction was used to categorize Ae. aegypti into subspecies. Adult female Aedes mosquitoes identified formed 62% (n = 1,206) of all female mosquitoes collected. Aedes aegypti 98% and Aedes vittatus 2% were the only Aedes species identified. Bolgatanga recorded the largest number of Ae. aegypti 42%, whereas Nadowli 22% recorded the least. Aedes vittatus was observed in Nadowli. Aedes aegypti exhibited a bimodal biting behavior peaking at 0600–0800 GMT and 1500–1600 h GMT. Molecular findings revealed 69% Ae. aegypti aegypti and 31% Ae. aegypti formosus as the two subspecies (n = 110). This information is important for implementing effective vector control programs in the three regions of the northern Ghana.

<p>The use of chemical insecticides in crop production has resulted in increased food production in Africa, but their use has resulted in the destruction of beneficial organisms and development of resistance by some insects to the insecticides. The effectiveness of garlic <em>Allium sativum</em> and hot pepper, <em>Capsicum frutescens</em> in controlling the pests of cabbage, <em>Brassica oleracea</em> was evaluated. These botanicals were compared with a standard chemical insecticide Attack® (Emamectin benzoate). The experiment was conducted in a randomized complete block design, with 3 treatments and a control, each of which was replicated 3 times. <em>Plutella xylostella, Brevicoryne brassicae, Hellula undalis</em> and <em>Trichoplusia ni</em> were found on cabbage plants. Significantly fewer of them were found on the treated plants than the control plants. The use of the plant extracts resulted in a reduction in mortality ranging from 10.76% to 55.94%. Fewer natural enemies of <em>B. brassicae</em> were sampled on the insecticide-sprayed plots than the garlic and pepper-sprayed plots. The cost of protecting cabbage plants from insect infestation using Attack was higher than the botanicals. Garlic-treated plots recorded the highest cost: benefit ratio of 1:16 while Attack®-treated plots recorded the least of 1: 9.2. The control effects of the botanicals compared favourably with that of the chemical insecticides. Thus these botanicals can be used as substitutes to chemical insecticides.</p>

The use of chemical insecticides in the control of insect pests has left in its wake resistance of some pests to some of the conventional insecticides. Alternative methods of managing pests such as cultural control have to be employed to reduce pest infestation of crops. Onion was used in an intercrop as a non host crop to manage the pests of cabbage. The experiment was conducted in a Randomized Complete Block Design with four treatments; sole cabbage (T1), 2 rows of cabbage to 1 row of onion (T2), 3 rows of cabbage to 1 row of onion (T3) and 4 rows of cabbage to 1 row of onion (T4), each of which was replicated three times. Data were collected on pests' numbers, plant height, damaged leaves at harvest, canopy spread, number of damaged heads and fresh weight. Significantly fewer Bemisia tabaci, Hellula undalis and Brevicoryne brassicae infested the intercropped plants than the sole crop. However, intercropping cabbage with onion did not significantly reduce Plutella xylostella population on cabbage. Number of damaged heads, fresh weight and damaged leaves were significantly different (P< 0.05).

The effects of ethanolic extract of neem, Azadirachta indica (Meliaceae), seeds and petroleum ether extract of Lantana camara leaves (Verbenaceae) on the populations of three cabbage pests, Plutella xylostella, Brevicoryne brassicae and Hellula undalis were studied. The study was conducted between January and April 2008. Extracts of the two plants were sprayed on cabbage plants to control these pests. A standard synthetic chemical insecticide (Mektin) was used as reference product. The experiment was conducted in a randomized complete block design and each treatment was replicated four times. The effects of plant extracts on the population dynamics of the pests' species, the level of infestation and yield were assessed. Significantly more of the pests infested the control plants than the treated plants (P< 0.01). The mean weight of cabbage heads on the sprayed plots was significantly heavier than that of the control unsprayed plots. The use of A. indica seeds and L. camara leaf extracts increased yield by 37.05% and 25.80%, respectively. Spraying the cabbage plants with the plant extracts significantly reduced the numbers of pests compared with the control plants. The use of these plant extracts can be incorporated into an overall control programme of these pests.

BackgroundThe increasing spread of insecticide resistance in malaria vectors has been well documented across sub-Saharan Africa countries. The influence of irrigation on increasing vector resistance is poorly understood, and is critical to successful and ethical implementation of food security policies. This study investigated the insecticide resistance status of An. gambiae (s.l.) mosquitoes collected from the irrigated rice area of Okyereko, a village containing about 42 hectares of irrigated field within an irrigation project plan in the Central Region of Ghana. Large amounts of insecticides, herbicides and fertilizers are commonly used in the area to boost the annual production of the rice.MethodsMosquito larvae were collected and adults were assayed from the F1 progeny. The resistance status, allele and genotype were characterized using WHO susceptibility testing and PCR methods respectively.ResultsThe An. gambiae (s.l.) populations from Okyereko are highly resistant to DDT and pyrethroid insecticides, with possible involvement of metabolic mechanisms including the elevation of P450 and GST enzyme as well as P-gp activity. The population was mostly composed of An. coluzzii specimens (more than 96 %) with kdr and ace-1 frequencies of 0.9 and 0.2 %, respectively.ConclusionThis study brings additional information on insecticide resistance and the characterization of An. gambiae (s.l.) mosquitoes from Okyereko, which can be helpful in decision making for vector control programmes in the region.

No abstract

The trial was to study the effect of different mulching materials on agronomic characteristics, pests and their subsequent effect on the natural enemies of the pests of pepper (Capsicum annuum).

<p>Cowpea, <em>Vigna unguiculata</em> is widely cultivated in the tropics and subtropics as food for man and livestock. The crop is highly prone to pests and diseases which limit its production. Resistant cowpea varieties have become increasingly important in the management of both field and storage pests. Three improved cowpea varieties and one local variety were screened for their susceptibility to field and storage pests. The experiment was conducted in a randomized complete block design with four treatments and three replications. The different pests infesting the plants were identified and counted. Aphids and thrips were scored on a scale of 0-5, depending on the levels of infestations. Natural enemies’ numbers, leaf damage, pod damage and yield were assessed. <em>Callosobruchus maculatus</em> infestations during storage and weight reduction were determined over a six week period. Aphids and <em>M. sjostedti</em> score, <em>M. virtrata</em> and <em>Empoasca</em> sp. numbers did not differ significantly; however, significantly more pod sucking bubs attacked the local variety than the improved varieties. Natural enemies’ numbers on the various cultivars did not differ significantly. Yield was however significantly better in the improved varieties. The local variety suffered the largest weight reduction (20.91%) during storage while Nhyira suffered the least weight reduction of 4.23%. The use of improved varieties and application of pests’ control measures will increase cowpea production in Ghana.</p>