Herbivory by insects and mites on physic nut (Jatropha curcas L.) seedlings was investigated and compared with irrigation in the semi-arid Sahelian Niger, utilizing a randomized complete block design experiment. Three water treatment protocols were applied and the types of damage were recorded. Less than 5% of the seedlings died during the 10-month trial period with sap suckers causing the most damage on the surviving plants. Plants with high production of biomass and leaf cover (foliage) were most strongly positively correlated with irrigation and were also the plants that endured the highest degree of herbivory. The low dieback may indicate that defence mechanisms counteract seedling herbivory and that drought-stressed plants invest more in their defence mechanism system than vital plants.

This study presents an interpretation of the way the Punjabi farmers in a village of the arid Sind perceive the pest hazard and the methods of management that they employ to deal with this situation. It is found that farmers do recognize the seriousness of the problem which consequently leads them to employ traditional as well as pesticide treatment of their crops. But because of financial handicap and other factors, they do not use pesticide regularly or in adequate quantity. As a result the control of pests remains ineffective.