Phytochemical Screening of Selected Botanicals and their Effectiveness Against Maize Weevil (Sitophilus Zeamais Motsch.) at Paklihawa, Rupandehi, Nepal

Laboratory experiment was done to perform the phytochemical screening of six locally available botanicals (Azadirachta indica Juss, Artemisia dubia Wall, Lantana camara L, Parthenium hysterophorus L, Justicia adhatoda Linn. and Moringa oleifera L.) and their effectiveness to control the maize weevil (Sitophilus zeamais Motsch.) at Agriecology lab of Institute of Agriculture and Animal Science, Paklihawa Campus, Rupandehi, Nepal. Seven treatments (leaf extract of A. indica, A. dubia, L. camara, P. hysterophorus. J. adhatoda and M. oleifera and distilled water as control) applied at 3 different doses (0.5, 1 & 2g/50g seeds) were arranged in CRD design with 3 replications. Result of mortality test of maize weevil revealed that, at highest concentration of L. camara powder (T17- 2g/50 gm seeds) mortality of maize weevil was observed up to 85% at 45 DAT. Whereas number of damaged grain was lowest in T17 (L. camara powder- 2g/50 gm seeds). The effectiveness of botanicals was found to increase with increasing the concentration. Besides that, Justicia adhatoda (2g/50g seeds) and Artemisia dubia (1g/50g seeds) were also found as good candidates to use for the control of Sitophilus zeamais. Qualitative tests done for the presence of various phytochemicals showed that Azadirachta indica Juss and Artemisia dubia Wall. were found to contain most of the tested metabolites among all botanicals. Most of those phytochemicals were extracted by the aqueous solution rather than other 3 menstrums used (acetone, methanol and petroleum ether). Similarly, quantitative test revealed that percentage of alkaloid was found 18.01%, 17.78%, 17.75%, 11.58%, 8.20%, 6.78% and flavonoid15.32%, 13.63%, 12.86%, 11.36%, 7. 51% 2.85% respectively in L. camara L. P. hysterophorus L., J. adhatoda Linn., M. oleifera L., A. indica Juss. and A. dubia Wall. Leaf extract of L. camera found to contain highest botanicals extract reach in alkaloid and flavonoid mayhave insecticidal property and could be use as grain protectant percentage of alkaloid (18.01%) as well as flavonoid (15.32%) So, it was concluded that the locally available against the maize weevil at storage condition in cost effective and eco-friendly manner; however, application at proper dose is necessary to maintain the efficacy at higher level.

Foraging ability of maize weevil in several varieties under dark and light conditions

Laboratory research to investigate the ability of maize weevil to find food source in the dark and light condition had been conducted in laboratory of pests and plan diseases of Indonesian Cereals Research Institute, Maros, South Sulawesi. This research was arranged in complete random design with three replications. There were six maize varieties put into small glasses and placed in circle within big jar and then invested with 100 heterogenous adult maize weevils in each jar. As a control, an empty glass was put in the center of glasses circle within the jar. Observation and calculation on living and dead maize weevils on each glass and outside glass was conducted with intervals of 24, 48 and 72 after maize weevil infestation. This research was performed in the light and dark condition. Result of the research showed that maize weevil ability to find their food sources was not determined by the light and dark. In addition, from this research, it was found that there were influence of corn variety as food resources, but this factor of variety as food resources needs to be examined further. The implication of this study are about the maize varieties attracted the weevil.

Natural Products: Are They Efficient Alternatives against the Stored Grain Pest Sitophilus zeamais?

Cereal crops strongly contribute with the world economy and because of this the reduction of their productivity may lead to irreparable economic consequences worldwide. The maize weevil Sitophilus zeamais is the main pest of maize in the field or during processing, storage and commercialization of grains, also attacking processed food. The population control of S. zeamais uses a restrict panel of synthetic insecticides which are associated with environmental contamination, selection of resistant individuals and toxicity to non-target organisms, including humans and other animals. This scenario has stimulated the search for new insecticides and plant metabolites stand out because of their high degree of biodegradability and more selective toxicity. This work provides a review of the effect of plant compounds on S. zeamais to encourage the use of these ingredients in more ecofriendly strategies for pest control. Plant insecticides can exert their toxicity by ingestion, contact and/or fumigation resulting in damage to the development, survival and reproductive potential of S. zeamais, or may present food deterrent activity, which protects the substrates from the attack by the insects. The data reviewed contribute to consolidate the use of natural products in control of S. zeamais.

Indigenous maize seed storage using buffalo dung ash practiced by smallholder farmers in Kisar Island

Kisar island is a small island located on the tip of Timor island. Corn is the main agricultural crop, and livestock husbandry also plays an important role in the livelihood of the farmers as a source of income, provide mainly manure for maintaining soil fertility. and in the local culture as a 'bride price' and for the exchange of goods. Considering periodical seasonal hazards, during eight months dry season people suffer from a serious shortage of water. Failure of the harvest is not an unusual phenomenon on the small, dry, eroded coral island. Seasonal pest invasion on maize cultivation threaten their seed security and food security. The objective of this review is to describe the validity of farmers’ indigenous knowledge (IK) of using buffalo dung as a preservative agent in maize storage and its relevancy in the contemporary living of farmers in the island. A phenomenological study was held in June to August 2018. The results showed that applying buffalo dung ash makes the maize dry faster, cleans and kills maize weevil and preserves the grain, It was concluded that the knowledge and practice is scientifically valid and benefited community in the past but has less relevancy to the contemporary living of the farmers in the island.

Abundance and diversity of insects associated with stored grains and tamarind in Nigeria

Detailed information on insect pests of stored grains in Nigeria is lacking. A two-year survey was conducted to determine the species composition and abundance of insects associated with maize, millet, rice, sorghum and tamarind in eighteen locations across five agro-ecological zones in Nigeria. Sixteen coleopteran, lepidopteran and hymenopteran species were associated with stored products, with high species richness on cereal grains but low species richness on tamarind. Most of these insects are polyphagous on cereal grains, whereas the tamarind weevil Sitophilus linearis (Herbst, 1797) (Curculionidae), and Caryedon serratus (Oliver, 1790) (Chrysomelidae) were found only on tamarind in this study. The maize weevil Sitophilus zeamais (Motschulsky, 1758), rice weevil Sitophilus oryzae (Linneaus, 1763), lesser grain borer Rhyzopertha dominica (Fabricius, 1792) (Bostrichidae), rusty grain beetle Cryptolestes ferrugineus (Stephens, 1831) (Laemophloeidae) and red flour beetle Tribolium castaneum (Herbst, 1797) (Tenebrionidae) were most abundant on stored grains. The tamarind weevil, C. serratus and the sawtoothed grain beetle Oryzaephilus surinamensis (Linneaus, 1758) (Silvanidae) were most abundant on tamarind. The hymenopterans Theocolax elegans (Westwood, 1874) (Pteromalidae), Anisopteromalus calandrae (Howard, 1881) (Pteromalidae) and Cephalonomia waterstoni (Gahan, 1931) (Bethylidae) were the dominant parasitoids of larvae and pupae of the storage pests. Simpson index of diversity of insect species across locations ranged from low (0.63) to high (0.89).

Contact Toxicity Effects of Selected Organic Leaf Extracts of Tithonia diversifolia (Hemsl.) A. Gray and Vernonia lasiopus (O. Hoffman) against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

Maize weevil (Sitophilus zeamais) infestation results in a substantial reduction in the quantity and deterioration of the quality of stored maize. Most farmers control weevils using conventional pesticides which are usually associated with several human health risks as well as intoxication of the fauna and flora. However, bioinsecticides form an alternative intervention since they possess fewer side effects on human health, are ecofriendly, and are readily available. This study sought to validate and document, in a systematic way, the pesticidal properties of the species Tithonia diversifolia and Vernonia lasiopus used for many years by many people of the world on S. zeamais. The plant leaf samples were obtained from Embu County, Kenya. Dichloromethane and ethyl acetate solvents were used to extract active phytochemicals from the dried plant sample powder. The GC-MS analysis of the obtained extracts was performed at ICIPE laboratories to identify their phytochemical compositions. Twenty grams of maize grains were put in 50 ml plastic vials and admixed with different treatments. The positive control group was treated with Actellic Super™, while the negative control was treated with the respective extracting solvent only. The experimental groups were separately treated with the plant leaf extracts at doses of 25, 50, 75, and 100%. After treatment, each of the six groups was infested with 10 male S. zeamais and weevil mortality as a result of contact toxicity of the treatments was assessed at 6, 24, 48, 72, and 96 hours after the insects were exposed to the extracts. Results of the study indicate that the selected organic leaf extracts of T. diversifolia and V. lasiopus possessed significant contact insecticidal effects that ranged between 1.67 to 99.98%. Furthermore, the GC-MS analysis revealed several active biocompounds in T. diversifolia and V. lasiopus extracts, which are known for their considerable insecticidal effects. Our data suggest that the organic leaf extracts of T. diversifolia and V. lasiopus have considerable insecticidal properties and would, therefore, be a valuable bioprotective agent for stored maize grains against S. zeamais.

Assessment of Insecticidal Potency of Eggshell Powder Against Maize Weevil

Efficacy of chicken eggshell powder at concentrations 0, 0.25, 0.5, 1.0 and 2.0 g /100 g maize, for control of Sitophilus zeamais, were compared with permethrin at dosage rate of 0.167g / 100 g of yellow maize. Experiments were conducted at Biotechnology laboratory (NSPRI), Ilorin under ambient condition (26±3oC 65±5% RH). Mortality of S. zeamais increased with increasing dosages of the CESP as well as with days of exposure. CESP at 2.0g gives 96.67% mortality which is not significantly different from the positive control. The mean progeny emergence (0.00%), weight loss (1.11%), and percentage grain damage (19.68%) by S. zeamais was significantly (P ≤ 0.05) decreased with increased dosage of CESP. However, CESP did not significantly affect seed germination. Total coliform count at 2.0 g (2.48 x 102) was significantly different from both positive and negative controls at p<0.05 Therefore, CESP can serve as a good maize protectant which can be used as substitute for synthetic chemicals.