Hence, the aim of this study was to determine the effect of aqueous extract of leaves obtained from six weeds viz., A. Botanical extracts that contain alkaloids and flavonoids were found to have ovicidal property against Meloidogyne eggs. Many botanical extracts have been found to contain phytochemicals such as alkaloids, tannins, saponins, flavonoids, diterpenes, glucosinolates, acetylenes and thienyls which are effective against plant-parasitic nematodes. Hence, the use of plant extracts is gaining attention due to their availability, cost effectiveness, pollution-free and enivironmently safe. Therefore, there is a necessity to search new, cheap and eco- friendly methods of nematode management. Though, the use of nematicides has been the most effective method for the root- knot nematode management, but they are hazardous in nature. The root- knot nematode is controlled through the use of chemical nematicides, crop rotation, organic amendments and biocontrol agents. The pest is the most pathogenic nematode in agriculture, causing an estimated yearly crop loss of $100 billion worldwide. Root- knot nematode attacks over 2000 plant species causing stunted growth and finally low yield. This pest is responsible for approximately 50% of overall damage. It damages a broad range of crops particularly vegetable crops, causing dramatic yield loss mainly in tropical and subtropical agriculture. The root- knot nematode, Meloidogyne spp. This suggests that the microbial counts play an important role in increasing antagonistic effects of the microfauna against soil-borne diseases (Panneerselvan and Saravanamutha, 1996 Harman, 2006). can be used as biological control of some soil-borne fungal diseases causing significant yield losses in legumes. Shaban and El-Bramawy (2011) also suggested that the Rhizobium spp. viride application significantly increased the growth components of potato. Myco-parasitism, spatial and nutrient competition, antibiosis by enzymes and secondary metabolies and induction of plant defence are typical biocontrol actions of these fungi (Dababat and Sikora, 2007 Verma et al., 2007 Gajera et al., 2013). Due to higher activity of Trichoderma, as bio- control agent due to the lytic enzymes production, compared to other soil microorganism that produce the same class of enzymes, therefore, Trichoderma has been widely used as antagonistic fungal agents against several pests as well as plant-growth enhancers. The ability to produce lytic enzymes is a widely distributed property of rhizosphere-competent fungi and bacteria. They reported that the use of specific mycolytic soil micro-organisms to control plant pathogens is an ecological approach to overcome the problems caused by standard chemical methods of plant protection.

These results are in agreement with those recorded by Viterbo et al.

Nematodes as biocontrol agents pdf