The variegated grasshopper, Zonocerus variegatus (Linnaeus) is a tropical insect which belongs to OrderOrthoptera and Family Pyrgomorphidae. In Nigeria,it is an insect which has been known to have resistance to commercial insecticidesand usually occurs on uncultivated land withthe nymphs and adult stage sharing the samehabitat which extends from Rain Forest zone to the Guinea Savannah in the north (Ademolu et al., 2011).
- variegatus is a seasonal pest (Kekeunou et al.,2006) which has a huge population during dry season in north-eastern Nigeria. Z. variegatus is a pest and vector of diseases of rice in different countries in Africa and around the world (Nwilene et al.,2009). Bamidele and Muse (2012) observed two different populations termed dryand wet season populations in Nigeria. They opined that the dry- season population constitutes grave pest problem for farmers, damaging several crop plants especially cassava during the dry season. Z. variegatus starts active feeding early in the morning between 6-8 am. (Okonkwo et al., 2011).Similarly, Oyegoke et al., (2011) opinedthat plants are some of the primary factors thatdetermine feeding in grasshoppers.Itsabundance in nature depends on the type of vegetation cover in a region with forest,Chromolaena odorata much more favoured (Kekeunou et al., 2007).
- variegatus is the dominant species among grasshoppers in many farmlands in Nigeria and in Africa (Oku et al., 2011). Therefore much attention has been focused on the destruction of this insect, than on its preservation and growth as a potential alternative food source. (Müller et al., 2002; Ogunlabi and Agboola, 2007).
The indiscriminate use of pesticides especially by merchants and farmers to protectagricultural products with its attendant adverse effects on man, the environment, nontarget organisms as well as the evolution of resistant strains of insect pests has been aserious set back to ecological safety (Dauda et al., 2012). Babarinde et al. (2009)state that the use of botanical product is unlikely to cause any health hazard to human especially those are used in food or water treatment.
Studies by Freitaset al., (2010) reveal that Moringa oleifera had toxic effects on mosquitoes and other insects, this resulted in the interest on Moringa species for their outstanding economic effects. M. oleifera, the most prevalent species, having nutritionaland medicinal uses has proved to be the most outstanding Moringaspecies (Aroral et al.,2013). Of recent, few others like Moringa stenopetala, M. peregrine and M. concanensis have been revealed to be having equal potentials such as nourishing vegetables, high-quality seed oil. Oils extracted from Moringa and their seeds were reported to have been used against Callosobruchus maculatus on the cowpea grains in storage (Ilesanmi and Gungula, 2010). Khater(2012) stated that some essential oils cause direct toxicity to insects, oviposition and feeding deterrence, repellence and attraction against the insects of the several Orders like Lepidoptera, Coleoptera, Diptera, Isoptera and Hemiptera.
1.1 Statement of the Problem
Synthetic insecticides have been proved to be persistent, and not easily biodegradable hence have adverse effects on abiotic and biotic components of the environment and humans.The challenge of finding a good alternative to replacing these conventional insecticides has led to bioprospecting for plants with natural insecticidal potentials yet with little or no effect on the environment and well-being of man. Man’s continued use of synthetic insecticides for insect control has altered natural ecosystem and led to increase in population of insects with resistanceand further adverse effects on living organisms and the natural environment.
The aim of this study is to evaluate the insecticidal effects of M.oleiferaseed extract and Moringa leaf powder on grasshopper(Z. variegatus).
1 To determine the phytochemical properties of Moringa oleiferaseed extract.
2 To evaluate the effects of M. oleifera seed extract and leaf powder on the body weight of Z. variegatus.
3 To evaluate the effects of Moringa seed extract and Moringa leaf powder on behaviuoral responses of Z. variegatus.