Potential use of Clerodendrum capitatum extracts and its formulation for control of three major stored product beetles

Abstract

Objective Insecticidal activity of Clerodendrum capitatum extracts against the stored product insect pest, Sitophilus oryzae (L.), Rhyzopertha dominica (F.), and Tribolium castaneum (Herbst) were investigated. Materials and Methods Hundred grams of C. capitatum powder was sequentially extracted with a series of solvents of increasing polarity in a Soxhlet apparatus and the extracts were concentrated on rotary evaporator to make it solvent free and the residue dissolved in a known volume of methanol and the solution was assayed for insecticidal activity by the fumigant toxicity. Hexane extract which showed maximum activity was selected for the preparation of herbal formulation and for its insecticidal properties and phytotoxicity. The herbal formulation obtained from leaves of C. capitatum was investigated by GCMS and GC/FID. Results Clerodendrum capitatum ethyl extract had a very strong repellent activity to adults of all three major stored grain insects and was significantly repellent at a 1.58 mg/cm2. The hexane extract (oil) had high fumigant activity with LC50 values in the range between 25 and 32 µg/L. A total of 14 components representing 97.8% of the formulation were identified and the main compounds in the formulation were found to be 2-Heptanone, 3-methyl (33.9 %) and Hexahydrofarnesyl acetone (25.3%) followed by 3-Dodecen-1-al (10.2%) and 8-Methyl-1-undecene (4.9%). Further, herbal formulation was found to be highly toxic to mixed age cultures of all three major stored grain insect pests which recorded 80%–90% mortality at dose of 200 µg/L in 24 h exposure, where as 100% mortality achieved at dose of 200 µg/L in 72 h exposure, respectively. Conclusion The results indicate that extracts and formulation of C. capitatum has the potential to be developed in to a natural insecticide or repellent for controlling of stored product beetles.

Efficacy of Aromatic and Medicinal Plant Powders against Callosobruchus maculatus F. (Chrysomelidae: Bruchinae)

“…18 Some post-harvest storage methods may also be useful to reducing cowpea bruch infestations as part of an integrated pest management approach. 19,20 The objective of this study is to evaluate the effect of the application of several Moroccan plants in powder form on the longevity, fecundity, emergence rate and duration of the larval phase of C. maculatus.…”

Screening of Vegetable Powders Used as a Bio-Insecticide Against Callosobruchus Maculatus F. (Chrysomelidae: Bruchinae)

“…Piper nigrum powder (Piperaceae) has caused a significant reduction in the bruchids population in cowpea stocks (Nwosu et al 2018), and similar results were obtained with Neem powder (Azadirachta indica A. Juss) (Neto et al 2019). Essential oils of Ocimum gratissimum L, and Ocimum basilicum L. have been successfully used against C. maculatus (Kéita et al 2001).Some post-harvest storage methods may also be useful to reducing cowpea bruch infestations as part of an integrated pest management approach (Singano et al 2019;Adesina et al 2019). The objective of this study is to evaluate the effect of the application of several Moroccan and imported plants in powder form on the longevity, fecundity, emergence rate and duration of the larval phase of C. maculatus.…”

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

“…Similar laboratory tests were carried out using extracts of 13 plants to assess their repellent properties against the banana weevil [ 46 ]. A free choice bioassay system was also used to evaluate repellency effects of extracts and fractions from leaves of C. capitatum against three major stored grain insect pests, namely, S. oryzae , R. dominica , and T. castaneum [ 47 ].…”

“…However, synergistic or additive effects as a result of combination and interaction between phytochemicals cannot be ignored [83]. Furthermore, the repellent activities of the plant volatiles may not be limited only to its major constituents; it could also be due to some minor constituents or a synergistic effect of several constituents [47]. Actellic ® 25EC, is a broad spectrum insecticide.…”