Insects and Their Products as a Potential Source of Food, Feed and Economic Security: A Review

Due to many ways by which they are exploited, insects and their products could be a very big business. They are sold for agricultural protection, crop pollination, as well as human, livestock and pet nutrition. In addition, their products are sold for pharmaceuticals, health, and the implements for research, art works and a host of other uses. This review focused on commercialization of insects and their products with a view of sharing existing knowledge on global commerce of various insects and their products. Available literature revealed that there was an increase in demand for edible insects in the United States of America and prices were as high as $150 kg-1. Similarly, between 2010 and 2015, animal feed market in the United Kingdom grew at 3.5% annually and is currently worth £5 billion. Because of its scarcity, high demand, and recognition of its healing properties, royal jelly, one of the most sought after from bee products commands astronomical price internationally. In addition, no any other industry could generate high level of employment as sericulture, especially in rural areas where it takes 11 workdays to produce a Kg of raw silk. The contribution insects and their products can give to improve the economy of a developing country such as Nigeria is considerable, but underestimated or neglected. Insects are unlikely to make a major contribution in the near future, but the idea that they are potential source of overcoming the economic problems is not as farfetched as it seemed. Therefore, there is the need to adopt an added value approach to insects and their products and sensitize as well as encourage small-scale farmers, who are disadvantaged in international market participation due to lack of access to information, services, technology or the capacity, to produce larger volumes of quality insect products.

Biocidal Activities of Seed Oils of Jatropha curcas and Moringa oleifera on Development of African Maize Stalk borer, Busseola fusca Fuller (Lepdoptera: Pyralidae)

Laboratory experiment was conducted at the Department of Crop Protection Laboratory, Faculty of Agriculture, Bayero University, Kano, in order to assess the effect of oils obtained from the seeds of Jatropha curcas and Moringa oleifera on African Maize Stalk Borer (Busseola fusca Fuller). The effects of the plant seed oils on larvae mortality, pupae and adult emergence were tested on freshly cut leaves/stem of maize 3-4 cm long) and treated with the prepared plant oils at various concentrations (10, 20, and 30%) and control (0%). The experiment was laid out in a completely randomized design and replicated four times. The results showed that both plant seeds oils were lethal to the developmental stages of B. fusca, causing mortality (21%) to the larvae, and subsequently preventing and/or suppressing pupae (2.08) and adult emergence (1.95). Treatment at 30% concentration was found to be more lethal to all the developmental stages of the test insect. Based on the findings of this study, it is recommended that any of the plant seed oils at 30 % concentration could be used to manage B. fusca.

Bioefficacy of Extracts of Hyptis suaveolens, Eugenia aromatica and Azadirachta indica as Field Protectants of Pawpaw Against Paracoccus marginatus Will. and Granara de Willink in Ibadan, Southwest Nigeria

The papaya mealybug, Paracoccus marginatus is a small sized polyphagous invasive hemipteran bug that attacks several genera of host plants, causing considerable yield loss. Commonly used insecticidal control is being discouraged due to environmental and human health hazards. Information on the control of this pest with botanicals is scanty, therefore the control using selected botanicals was investigated. Aqueous and ethanolic extracts of three botanicals: Hyptis suaveolens, Eugenia aromatica and Azadirachta indica were evaluated in screen cages (1.80×0.60×1.50m) for contact toxicity following standard procedures. Cypermethrin® (100 ml a.i ha-1) was used as a standard check. The secondary metabolites in the three plants were analyzed for saponins, alkaloids, terpenoids, phenols, flavonoids and cardinolides following standard procedures. Effective concentration was determined using probit analysis. Both aqueous and ethanolic extracts of the botanicals caused adult mortality of P. marginatus. However, the difference in percentage mortality in aqueous extracts of A. indica (54.28±1.7), H. suaveolens (47.5±4.1) and E. aromatica (48.6±1.1) were not significant (P>0.05). Percentage mortality of ethanolic extracts of A. indica (87.40±4.8) was significantly higher (P<0.05) than both E. aromatica (74.40.16±2.4) and H. suaveolens (72.10.58±2.8). Concentration of the secondary metabolites varied in the botanicals with H. suaveolens having higher flavonoids (107.08mg/100g), cardinolides (46.06 mg/100g) and terpenoids (3.17mg/100g) while A. indica had higher saponins (10.33mg/100g) and phenols (1938.48mg/100g) while E. aromatica had comparatively higher alkaloids (0.59%). The LC50 ranged from 3.61mg/kg in A. indica, to 4.64mg/kg in E. aromatica and 4.52mg/kg in H. suaveolens. The ethanolic extracts of botanicals evaluated were more effective than the aqueous extracts and can serve as a substitute to the synthetic insecticides for the control of P. marginatus.

Effectiveness of Selected Parapheromones for Mass Trapping of Mango Fruit Fly, Ceratitis cosyra Walker and Oriental Fruit Fly, Bactrocera dorsalis Hendel (Diptera: Tephritidae) on Mango

Mango (Mangifera indica L.) is an important fruit crop in Nigeria. It is a source of essential vitamins and is also cultivated for its nutritional, medicinal and industrial uses. Fruit flies infest various commercial fruit crops and cause economic damage. Mass trapping and male annihilation technique (MAT) has been the most useful and common means of controlling fruit flies with special focus on Bactrocera dorsalis Hendel (Diptera: Tephritidae) on mangoes. The study evaluated the effectiveness of four types of parapheromones namely, methyl eugenol (liquid and solid forms), cuelure, terpinyl acetate and trimedlure for mass trapping of fruit flies on Mango. Modified Lynfield traps containing the parapheromones were randomly set on the mango orchards in three replicates in Nigeria Horticultural Research Institute (NIHORT) orchard, Okigwe, Imo state, Southeast Nigeria. This study was conducted during the mango fruiting period of 2019 season, when the density of fruit flies peaked. Effect of parapheromones on mean number of damaged dropped fruits was also evaluated. The mean population of B. dorsalis and Ceratitis cosyra was significantly higher (P>0.05) in liquid methyl eugenol traps when compared to other parapheromones. Bactrocera dorsalis recorded more than 90% of the fruit flies that were trapped especially in the first 3 weeks of trapping. In orchard I, Liquid methyl eugenol significantly (P<0.05) trapped highest number of B. dorsalis (270.20) in week I and similar trends were observed in orchard II. There was steady decline in damaged dropped mango fruits as the study progressed (Fig. 1 and 2). Use of liquid methyl eugenol was most effective in trapping B. dorsalis and C. cosyra, and it can be incorporated in Integrated Pest Management (IPM) programmes for the control of fruit flies.

Comparative Efficacy of Jatropha curcas L. Seed Powder for the Control of Callosobruchus subinnotatus (Pic) on Stored Bambaranut, Vigna subterranea (L.) Verdcourt

The study was to assess insecticidal effectiveness of Jatropha curcas L. seed powder on Callosobruchus subinnotatus (Pic) infesting stored bambaranut, Vigna subterranea (L.) Verdcourt. The experiment was laid out in a factorial design of 4×2 levels (seed powder at the rates of 0.0, 0.5. 1.0 and 1.5 g, with and without addition of the synthetic insecticide at 0.01 g/20 g bambaranut seed) and laid out in a completely randomized design, in three replicates. Results obtained showed lowest oviposition, progeny emergence and seed damage (5.33, 1.58 and 1.83, respectively) in bambaranut seeds admixed with 1.0 g of the seed. Although, statistically similar to all other treatments, it was significantly (P≤0.001) better than the control treatment in which 33.83 eggs were laid and 24.08 adults emerged from 22.92 emergence holes. In addition, at six (6) days after treatment, highest adult mortality rate (99.17%) similar to that (99.17%) obtained in the synthetic insecticide was also recorded in seeds treated with 1.0 g seed powder. However, all other treatments were also significantly better than the control, in which 72.50% of the introduced bruchids died. Comparatively, lowest rate of seed damage (6.68%) and lasting effect was also obtained with the addition 1.0 g seed powder. In conclusion, appreciable level of protection on bambaranut seeds was achieved using seed powder of J. curcas. Therefore, it is recommended that for effective management of C. subinnotatus infesting bambaranut, farmers could use 5 Kg seed powder on 100 Kg bambaranut seeds.

Larvicidal Activity of Aqueous Pod Extract of Adansonia Digitata (Linnaeus, 1753) on Culex Quinquefasciatus (Say, 1823) Maulik

The study evaluatrd the effect of Baobab, Adansonia digitata pod extract on larvae of Culex quinquefaciatus. The plant material was sun-dried for two weeks and pulverized using mortar and pestle and stored at room temperature for further processes. Powdered plant material was extracted using aqueous cold extraction method. The condensed extract was screened for phytochemicals. Indoor resting adult blood-fed female Culex mosquitoes were collected and introduced into Entomological Cages in the Laboratory and oviposited on water in the bowls. The third instar larvae were confirmed as Cx. quinquefasciatus using Hopkins keys for Culicinae. Triplicates of twenty-five late third instar larvae were tested in pod extract concentrations of 0.5mg/L, 1.0mg/L, 1.5mg/L, 2.0mg/L and 2.50mg/L. Mortality was recorded after 24hr of exposure. The LC50 was determined using probit analysis, while one-way ANOVA was used to establish significant differences in larval mean mortality. Phytochemical constituents such as carbohydrate, cardiac glycosides, steroids, triterpenes, tannins, flavonoids and alkaloids were present. The mean mortality of test concentrations differed significantly (p≤0.05) from control. However, the concentrations: 0.5mg/L and 8.0mg/L had 49% and 71% mortalities, respectively with LC50 of 0.6mg/L. It can be concluded that, the aqueous pod extract of Adansonia digitata demonstrated good activity against Cx. quinquefasciatus. Adansonia digitata pod extracts has potential for controlling larvae of Culex mosquitoes and can be incorporated into integrated mosquito management programme.

Residual Content of Persistent Insecticides in the Fresh Nuts of Cola Acuminata Cohac from Kumbotso Local Government Area of Kano State and Implication for Public Health

The pesticide residues in kola nut, Cola acuminata obtained from Mariri Market, Kumbotso Local Government Area, Kano state of Nigeria was investigated. The study consisted of a survey and laboratory analysis of kola nut samples. One hundred structured questionnaires were administered through an open market format in the major kola nut market in the state. In addition, 1kg sample of kola nut was collected randomly from ten major kola nut sellers in the market for analysis. A 100g sample of the kola nut was pounded into paste in a blender of which 50g was soaked in 150mL acetone for 24h. The extracted sample was filtered through anhydrous sodium sulfate while the extract was evaporated to near dryness using a rotary evaporator at 28oC in the Laboratory. Residue was redissolved in 2 mL acetone and kept in the refrigerator for GCMS Analysis. Ten pesticidal compounds were detected from a comparison of data with reference to mass spectrometry data (NIST05.LIB) and significant occurrence in kola nut sample which had a corresponding molecules affiliated to some pesticides standards were detected in the sample

Bioefficacy of Some Botanicals Against Gum Arabic Borer, Bruchus baudni Caill (Coleoptera: Bruchidae) on Stored Senegalia senegal Seeds

The use of bio-pesticides has proven to be successful approach in controlling agricultural insect pests. Study was conducted in the Laboratory of the Department of Crop Protection, Faculty of Agriculture, Bayero University, Kano to study the Biology of Bruchus baudni on treated Senegalia senegal seeds. Seed oils and leaf powders of K. senegalensis and M. oleifera at three concentrations each, a chemical insecticide (Aluminum phosphide as standard check) and a control were laid out in a Completely Randomized Design (CRD) and replicated three times. Data collected were oviposition, egg hatchability and developmental stages. The results indicated significant reduction in the number of eggs laid (1% and 1.38%) and hatchability (0.00% and 0.57%) on both seed oil and leaf powder treatments, respectively; however, the control recorded the highest eggs laid (99.9%) and number of emerged B. baudni (99.2%). The present findings showed that seeds and leaves of mahogany and moringa were effective as protectant against some of the development stages of B. baudni. Therefore, based on the present results, mahogany and moringa seeds and leaves could be explored to replace the synthetic insecticides in the management of B. baudni especially as components of integrated pest management strategy.

Effect of Planting Dates on Incidence of Legume Pod Borer (Maruca vitrata Geyer) on Cowpea (Vigna unguiculata (L.) Walp.) Varieties in Samaru Kataf, Kaduna State

Field experiment was carried out during 2018 cropping season to evaluate the effect of planting dates on incidence of legume pod borer Maruca vitrata on cowpea (Vigna unguiculata) varieties. The treatments consist of five varieties of cowpea (local variety, SAMPEA 6, SAMPEA 7, SAMPEA 8 and SAMPEA 10) which were sown at three different dates, 7th (early), 24th (Mid) August and 7th (early) September, 2018. The experiment was laid out in a Randomized Complete Block Design (RCBD) replicated three times. The number of M. vitrata larva on flowers, damaged pods and weight of grains were determined. The result showed that first sowing nearly August had less infestation by M. vitrata than those in mid August and differs significantly (P≤0.05) from those sown in September. All varieties sown in early and mid August had less M. vitrata infestation and produced higher grain yield of 533.33kg and 395.06 kg on SAMPEA 7 and SAMPEA 8, respectively compared to those sown in early September: 256.79 and 197.53 on SAMPEA 7 and SAMPEA 10, respectively. Local variety and SAMPEA 6 were the varieties with higher mean number of M. vitrata, higher pod damage and low grain yield. Therefore, SAMPEA 7 can be utilized in breeding program for the management of pod borer.

Distribution and Abundance of Spider Fauna in Zaria Local Government Area, North West, Nigeria

Spiders are among the most diverse arthropod groups of organisms. This study investigated the distribution and abundance of spiders in five locations in Zaria Local Government Area of Kaduna State, Nigeria. The study was conducted for five months, from April to August, 2018. Samples were collected twice each month using vegetation beating, trapping using bottle and handpicking methods. The abundance of each species of spider identified was expressed in percentages while diversity was revealed using Shannon-Wiener diversity index. A total of 217 spiders were collected from all the study locations which belong to 14 families, 24 genera and 28 species. The study locations differ in terms of vegetation, topography and habitat structures. Family Lycosidae was found to be the dominant family which include four genera and five species, followed, by Agelenidae, Amaurobidae and Gnaphosidae which have a species proportion of 10.7% each and 3 species abundance. Area II (Tudun Serika) the most diverse, with 60 spiders collected in this area, belonging to 11 families, 18 genera and 19 species. Area IV (_________) was the least in terms of spider species diversity and abundance with only 12 spiders, belonging to four genera and four families. Cesonia bilineata had high dominance index of 1.315. There is need for proper documentation of spider species available in Nigeria.