3.1 Yield of seed extracts
The Soxhlet extraction is one of the simple, useful and well known universal extraction technique. In seed extraction the polarity of solvent and time required for extraction process plays an important role in extraction efficiency. As displayed in (Table 1) the percentage yield obtained of all extracts were good however, highest yield was obtained in P. hexandrum 67.9% followed by R. pseudoacacia 57.5%, A. virdis 56.1%, M. neglecta 50.4 and T. officinale 40.3%. The lowest yield was observed in seed extracts of D. deltoidea 23.9% followed by A. precatorius 13.8% and B. persicum 12.4%. In this work the Soxhlet extraction gives comparatively good extraction efficiency of seed extracts that can play an important role in relation to their nematicidal nature.
3.2 Nematicidal activity
All the seed extracts tested were observed to exhibit good level of inhibition towards juveniles of M. incognita in vitro method, but the level of toxicity varied with increase in exposure time. It has been found that all extracts showed higher mortality rates following 72 h. Data presented in the (Table 2) showed that all the seed extracts showed suppressive activity against M. incognita which increases in increasing exposure time. However, dominant inhibition was shown by T. officinale (93.67%, 61.44% and 38.71%) and B. persicum (89.66%, 56.55% and 35.06%) mortality of M. incognita at 72, 48 and 24 hours respectively. The extracts of M. neglecta (75.28%, 55.73% and 36.67%) and R. pseudoacacia (70.39%, 48.66% and 36.43%) showed good inhibition of M. incognita while as normal effect was displayed by A. precatorius (67.62%, 41.19% and 34.33%), A. virdis (62.46%, 45.32% and 32.24%), D. deltoidea (62.37%, 42.22% and 31.47%) and P. hexandrum (60.31%, 40.33% and 34.53%) mortality of M. incognita at 72, 48 and 24 hours respectively. The results were confirmed by seed extracts of Ricinus communis and Peganum harmala which were used by Hasan et al. [13], Curto et al. [14] and Rich et al. [15] against Meloidogyne juveniles, and found them effective.
Laquale et al. [16] earlier reported that the leaf and root extracts of T. officinale showed 36 and 50% juvenile mortality and 14.8 and 23.8% egg hatchability reduction of M. incognita. Khan et al. [17] found that various extracts of plants from apiaceae family such as Coccinia grandis, Commelina benghalensis, Leucas cephalotes, Phyllanthus amarusand, Trianthema portulacastrum displayed good nematicidal activity against M. incognita.
In case of greenhouse method as presented in (Table 3) T. officinale and B. persicum extracts were found to be more potent than in reducing number of gall and number of egg masses in comparison to all other treatments. The seed extracts of M. neglecta, A. precatorius and R. pseudoacacia showed good inhibition of nematodes while as Lowest reduction was noticed in case of P. hexandrum and D. deltoidea as compared to control.