Residual insecticides, inert dusts and botanicals for the protection of durable stored products against pest infestation in developing countries

Insect pests associated with durable grains and processed food cause considerable quantitative and qualitative losses throughout the world. Insect infestation can occur just prior to harvest, during storage in traditional storage structures, cribs, metal or concrete bins, and in warehouses, food handling facilities, retail grocery stores as well as in-transit. Many tools are available for managing insects associated with grains and processed food. Although pest management strategies are changing to meet consumer’s demand for food free of insecticide residues, address concerns about safety of insecticides to humans, delay insecticide resistance development in insects and comply with stricter insecticide regulations, the use of synthetic residual insecticides will continue to be a major component of stored-product pest management programmes. Selective use of residual insecticides requires a through understanding and evaluation of risks, costs and benefits. The use of plant and inert materials may be a safe, cost-effective and environmentally friendly method of grain preservation against pest infestation among low-resource poor farmers who store small amounts of grains. There is a dearth of information on the use of plant materials by rural farmers in Africa for stored-product protection. The most promising candidate plant materials for future utilization as grain protectants are Azadirachta, Acorus, Chenopodium, Eucalyptus, Mentha, Ocimum, Piper and Tetradenia together with vegetable oils from various sources. Neem is the only plant from which several commercial products have been developed worldwide. However, unlike synthetic insecticides these alternatives often do not provide effective or rapid suppression of pest populations and may not be effective against all species of pests. These alternatives are also more expensive than synthetic insecticides, and have not been tested extensively under field conditions in the tropics. This paper focuses on the current state of the utilization of residual insecticides, inert dusts and botanicals by resource-poor farmers for protection of durable stored produce against pest infestation in Africa. A major research priority is a well designed on-farm trials to validate the efficacy of botanicals and inert dusts for stored-product protection using standard procedures and formulations that can be transferred to other communities. Key words: Botanicals, Residual insecticides, Inert dusts, Grain storage, Storage pests, Stored product

Field evaluation of non-synthetic insecticides for the management of insect pests of okra Abelmoschus esculentus (L.) Moench in Ghana

In a two-year study, aqueous seed extracts of the neem tree Azadirachta indica A. Juss (Meliaceae) and Bacillus thurigiensis (Bt) were evaluated in the field for the management of pests of okra, Abelmoschus esculentus (L.) Moench. The aqueous neem seed extracts were applied at the rate of 30, 50, 75 and 100 g/l and B.thurigiensis was applied at the rate 1.0 g/l of water. Actellic 25 EC, a synthetic insecticide, was applied at the rate of 2 ml/l as standard check. Arthropod fauna on okra were sampled using traps, sweep nets, aspirators and handpicking. The nature of damage caused to the stems, leaves, flowers and fruit was assessed by visual observation. The major insect pests of okra collected were Podagrica uniformis Jac, Aphis gossypii Glov, Sylepta derogata (F.), Spodoptera litoralis Boisd, Prodenia litura (F.), Dysdercus superstitiosus (F.), Epilachna similis (F.), Bemisia tabaci (Genn.) and Zonocerus variegatus (F.). These pests were observed attacking mainly the leaves of okra. Some of the minor pests identified were Lagria villosa (F.), L. cuprina Thoms, Mylabris temporalis Wellni, M. trifasciata (Thumb.), Lapidognatha sp and Empoasca devastans (D.). Actellic, neem seed extract and Bt significantly reduced the population and damage caused by the major insect pests of okra recorded at Legon, Ghana compared to the untreated. Actellic and aqueous neem seed extracts were equally effective against the pests of okra and caused a significant reduction in insect damage to the leaves, flowers and fruit of the crop. There were no significant differences among the different dosages of neem seed extract on all the parameters assessed, with the exception of the final fruit yield. Actellic, neem extracts or Bt produced higher yield of marketable fruit of okra than untreated plants. Neem seed extract applied at the rate of 30 g/l of water to okra plants produced lower fruit yield than those treated with 50 g or more. Aqueous neem seed extracts and Bt can be used effectively by farmers as a component of integrated management of pests of okra in Ghana. Key words/phrases: Bacillus thurigiensis (Bt), insect pests, neem seed extract, non-synthetic insecticides, okra SINET: Ethiopian Journal of Science Vol.26(2) 2003: 145-15

Some aspects of the biology and behaviour of Sesamia nonagrioides botanephaga Tams and Bowden (Lepidoptera: Noctuidae), a major stem borer pest of maize in Southern Ghana

Studies were conducted on the stemborer, Sesamia nonagrioides botanephaga Tams and Bowden (Lepidoptera: Noctuidae), which is a pest of increasing importance on maize in Ghana, to elucidate some aspects of its biology and behaviour in southern Ghana. The pest was more abundant in the minor season than in the major season. The life cycle revealed 10 developmental stages, namely the egg, six larval instars, prepupa and pupa. A female S. n. botanephaga laid eggs within a period of 5 days. The eggs were deposited on the inner side of the leaf sheath fitting tightly onto the maize stem. The mated females laid more eggs per female (330 + 17.7 eggs) than the virgin females (268 + 9.2 eggs). The incubation period of the eggs was 5.23 + 0.03 (5-7) days. The mean larval duration was 29 days and the prepupal period lasted for 1–3 days. The first instar larvae dispersed within 1–3 days after hatching. The third, fourth, fifth, and sixth instar larvae fed actively on maize stalk producing large quantities of frass. The pupal period varied from 6 to 10 days. The life cycle was completed in an average of 35.2 (26-51) days. Adults of S. n. botanephaga lived for between 4–10 days. The adults reared in the laboratory showed a sex ratio of 2:3 (male : female), which was significantly different from the expected ratio (1:1). The implications of these findings are discussed in relation to the effective management of the pest in Ghana

Temporary Migration in Africa: Views from the Global South

No Abstract

Field measurements and statistical analysis of perforated grating surfaces for grating fresh cassava into mash in Ghana

Processing of cassava into mash requires grating of fresh cassava tubers through the abrasive action of the grating surfaces of cassava graters that grind against the cassava and transforms it into mash. Over the years, improved cassava graters have been designed and made available on the market. In spite of improvements in design, there are no standards for the manufacture of grating surfaces and this affects interchangeability of the product. Mechanised grating of fresh cassava into mash contributes to reduce postharvest losses of cassava, increase its shelf life and improve food security. However, majority of the cassava grating surfaces are poorly made with substandard measurements that affect the desired particle size of mash for gari, a staple food for millions of people in West Africa. This study assessed cassava grating surfaces focusing on the abrasive elements (tooth diameter and inter-tooth spacing). Qualitative data were gathered from local metal fabricators and female gari processors in separate focus group discussions. The purpose was to gather the narratives underlying the issues being studied so as to complement and enrich the quantitative data. 112 tooth diameters and 112 inter-tooth spacing of perforated cassava grating surfaces were randomly measured in 16 different study areas in 3 regions of Ghana, namely Western, Central and Ashanti. Results from the qualitative data showed that grating of cassava was done repeatedly (about 2-3 times) before reaching the desired particle size of mash for gari. Most customers desire grating surfaces that ensure effective contact between the cassava and the metal grating surface to reduce grating time. Results from the field measurements showed high variation in existing tooth diameters (min=1.80, max=4.50 mm) and inter-tooth spacings (min=3.50, max=12.00 mm) that resulted in non-uniform particle size of cassava mash. Using statistical analysis, tooth diameters (min=3.18, max=3.42mm) and inter-tooth spacings (min=7.12, max=7.78mm) were determined at 95% confidence interval. For practical purposes, tooth diameter of 3 mm and inter-tooth spacing of 8 mm are recommended. The availability of such data will contribute significantly to standardise perforated cassava grating surfaces to achieve product interchangeability and desired quality of grated mash for gari. This will contribute to improve the manufacture of cassava graters and sustainable gari processing business in Ghana and Africa.Keywords: Fresh cassava, cassava grating surface, gari, food quality, Ghan

Toxicity, growth regulatory and repellent activities of medicinal plant extracts on Musca domestica L. (Diptera: Muscidea)

Housefly, Musca domestica, is a major vector for many medical and veterinary pathogenic organisms. The development of naturally occurring insecticides, represent one of the most promising approachesfor their ecochemical control. Petroleum-ether extracts of Griffonia simplicifolia and Zanthoxylum xanthoxyloides were assessed for their toxicity, growth regulatory and repellency to the housefly. Percent mortality and index of repellency induced by the extracts against the insects were found to be dose-dependent. Seed extracts of G. simplicifolia and root extracts of Z. xanthoxyloides were the mosteffective as toxicants and repellents against the fly. The LD50 in 24 h topical application of seed extracts of G. simplicifolia and root extracts of Z. xanthoxyloides were 0.28 and 0.35 ìg, respectively. Seed extracts of G. simplicifolia evoked a very strong regulatory effect against the second larval instar of the housefly. The RD50 of crude extracts of G. simplicifolia and Z. xanthoxyloides against housefly ranged from 1.0 to 6.8 and 1.3 to 1.7 ìg cm–2, respectively. Extracts of the two plant species may be useful as insecticides for controlling the housefly and should be exploited as a component of integrated vector control strategies or could be useful in the search of new larvicidal naturalcompounds

Influence of Different Seeding Dates on Fenugreek (Trigonella foenum-graecum L.) Forage Yield and Nutritive Value

Fenugreek (Trigonella foenum-graecum L.) is used as medicinal plant in many Asian countries and has been reported to have forage quality similar to alfalfa. Fenugreek is an annual crop and may have the potential to diversify forage production systems in the central High Plains. This study evaluated forage dry matter (DM) production and the nutritive value of three fenugreek cultivars as influenced by planting date at Hays and Garden City, KS, in 2014. Results at Hays showed forage DM yield of fenugreek cultivars was not affected by planting date, but fenugreek cultivars differed significantly (P \u3c 0.05) in forage DM yield. Averaged across planting date, forage DM production was 760 lb/a for ‘Amber,’ 910 lb/a for ‘F96,’ and 672 lb/a for ‘Tristar.’ Forage crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrient (TDN) concentrations, and relative feed value (RFV) did not differ (P \u3e 0.05) among fenugreek cultivars. Planting early, however, did increase CP levels and lower ADF and NDF concentrations. Despite the lower yields observed in 2014, our preliminary results showed that fenugreek can produce forage with nutritive value comparable to alfalfa and that further testing is needed to determine if fenugreek can provide an option for producers who want to diversify their forage production operations, particularly under limited irrigation conditions

Bioactivities of crude extracts of the candlewood Zanthoxylum xanthoxyloides Lam. (Rutaceae) against the cowpea beetle Callosobruchus maculatus (Walp)

The efficacy of petroleum-ether crude extracts of the candlewood, Zanthoxylum xanthoxyloides Lam. was assessed for their contact toxicity, feeding and oviposition deterrence to the cowpea beetle Callosobruchus maculatus (Walp). Percent mortality, number of progeny produced and damage caused to were dose– dependent. Root extracts was the most effective as toxicant to the beetles. The LD50 in 24 h topical application of root extracts was 4.98 μg. The LD50 (96 h toxicity in grain) suggests that root extract was highly toxic to C. maculatus. Development of eggs and larvae within grain kernels, as well as progeny emergence were significantly inhibited in treated grains. There were no progeny produced by C. maculatus in grains treated with dosage ³ 0.4 g per 100 g of grain. Root extracts provided the greatest protection of cowpea against feeding by C. maculatus with no observable feeding damage to grains treated with the highest dosages of the three materials. Extracts were repelled C. maculatus but with considerable variation in their repellent action. Z. xanthoxyloides contains phytochemicals, and crude extracts could be used as a botanical insecticide in alternative control strategies against C. maculatus. Keywords: Antifeedant, Bruchids, Botanical insecticides, Reproduction retardant, Toxicity. Int. J. Biol. Chem. Sci. Vol. 2 (3) 2008: pp. 316-32

The Implications of Insurance Status on Presentation, Surgical Management and Mortality among Non-Metastatic Breast Cancer Patients in Indiana

Background The National Breast and Cervical Cancer Early Detection Program seeks to reduce health care disparities by providing uninsured and underinsured women access to screening mammograms. The objective of this study is to identify the differences in presentation, surgical management, and mortality among nonmetastatic uninsured patients diagnosed through Indiana's Breast and Cervical Cancer Program compared with patients with private and government (Medicare or Medicaid) insurance. Methods Study data were obtained using the Indiana state cancer registry and Indiana's Breast and Cervical Cancer Program. Women aged 50 to 64 with an index diagnosis of stage 0 to III breast cancer from January 1, 2006 to December 31, 2013, were included in the study. Bivariate intergroup analysis was conducted. Kaplan-Meier estimates between insurance types were compared using the log rank test. All-cause mortality was evaluated using a mixed effects model. Results The groups differed significantly for sociodemographic and clinical variables. Uninsured Indiana Breast and Cervical Cancer Program patients presented with later disease stage (P < .001) and had the highest overall mortality (hazard ratio 2.2, P = .003). Surgical management only differed among stage III patients (P = .012). Conclusion To improve insurance-based disparities in Indiana, implementation of the Breast and Cervical Cancer Program in conjunction with expansion of insurance coverage to vulnerable low-income populations need to be optimized

Compensatory and susceptive responses of cowpea genotypes to infestation by aphis Craccivora koch.

The aim of the study was to estimate yield loss to10 selected genotypes of cowpea as a result of Aphis craccivora infestation during the vegetative phase of the crop. There were two trials with four replications. The first trial serving as the control was sprayed at the seedling, flowering andpodding stages against insect pests with lambda cyhalothrin (PAWA®). The other trial was sprayed only at flowering and podding stages. The cowpea seedlings of the second trial were infested with five four-day-old aphids per seedling two weeks after planting. The aphids were allowed to form colonies and fed on the seedlings until symptoms of damage were observed. When the susceptible seedlings became stunted with distorted leaves and yellowing of leaves at two weeks after infestation (28 days after planting), aphids were controlled. The results showed that aphids’ infestation delayed flowering and maturity of genotypes of cowpea. With the exception of early flowering genotypes all the medium to late flowering genotypes produced higher dry grain yield in infested plots than the control plots. The trend was not different from the production of dry biomass. The results of the present study implies that control of aphids infestation inearly maturing cowpea genotypes should not be delayed up to two weeks after infestation or 28 days after planting. Aphid’s infestation period for studies in susceptive response in medium to late maturing genotypes should go beyond 28 days after planting probably up to 35 days afterplanting