Preface   Fortunately, almost all kinds of vegetables are cultivated in India and there remain hardly any vegetables which is not cultivated here. A tremendous number of diverse vegetables, 175 in all are grown in different corners of the country. These are the highly valuable sources of carbohydrates, proteins, minerals and vitamins and thus play an important role in balanced nutrition of human beings. Among them one of the most important group is cucurbits. This is an important and a big group of vegetables. Basically most of the cucurbits are warm season crops, grown in a particular period of the year. But, due to development of advanced scientific agro-technology and unique agricultural inputs, these are now being grown round the year and thus meeting demand of daily dietary requirement of ever increasing population of our country. Like other vegetables, cucurbits are much more prone to insect pest attack mainly due to tenderness and softness as compared to other crops and virtual absence of resistance characters because of extensive hybridization. The extend of damage varies with plant type, location, damage potential of the pest involved and cropping season. Export of Indian vegetables is very low because of this higher domestic requirement and several other biotic and abiotic limitations in crop production. In many instances even cent percent yield loss reported to have been occurred due to these stresses. Successful cultivation of vegetables is hampered badly due to several biotic and abiotic stresses. Sustainable management of the pests of vegetables is really a complex issue in view of the tropical and sub-tropical climatic condition, intensive cultivation of high yielding and hybrid cultivars under high fertilisation and irrigated condition. Lack of adequate knowledge with regard to plant nutrition, protection and economic constraints added to the complexity of vegetable production. In the changing climatic condition the pest scenario is changing day by day. The invasive alien species of pests are not uncommon under free trade and frequent travelling of peoples from one country to another. A considerable portion of both pre harvest and post harvest crop losses have been witnessed every year.

1.1 Introduction ‘Cucurbits’ is a term coined by Liberty Hyde Bailey for cultivated species of the family Cucurbitacae. During this current century the term has been used not only for cultivated forms, but also for any species of the family Cucurbitacae. Cucurbits are frost sensitive, predominantly tendril-bearing vines which are found in subtropical regions around the globe. A few numbers of species those are native to or cultivated in temperate climate are prolific seed producing annuals or perennials that live for one season until killed by frost (Robinson and Decker-Walters 2004). Other vernaculars applied to the family Cucurbitacae and several of its members are ‘gourd’, ‘melon’, ‘cucumber’, ‘squash’ and ‘pumpkin’.

2.1 Insect Pests Insects are often a major obstacle to the successful production of cucurbits (York, 1992). They can severely reduce yield, injure or kill plants, spread diseases and adversely affect fruit quality. A number of insect pests, mites and nematodes have been found to infest cucurbitaceous vegetables but fortunately, in India, fruit flies and a few species of beetles are of economic importance; aphids and blister beetles though of regular occurrence, seldom cause severe damage.   Other insect pests reported to infest the cucurbitaceous vegetables are pumpkin caterpillar, Diaphania indica (Sounders), snake gourd semilooper, Plusia peponis Fab., white fly, Bemisia tabaci Genn., stink bugs, Apspongopus spp. and flea beetle, Phyllotreta spp. etc. These biotic pressures on the crops are increasing day by day due to round-the-year intensive cultivation of photo and thermo insensitive cultivars as well as indiscriminate use of toxic agro-chemicals in the present era of chemicalized agriculture.

Tremendous genetic diversity occur within different crops of this family with respect to their adaptability. Some cucurbits are grown in tropical, subtropical or arid deserts whereas other prefer to grow in temperate conditions. Harvested fruits and vegetables can be potentially exposed to numerous abiotic stresses during production, handling, storage and distribution (Hodges, 2003). However, when the abiotic stress is moderate or severe, quality losses almost always are incurred at market (Toivonen, 2003). Annually about 42% of the crop productivity is lost owing to various abiotic stress factors (Oerke et al., 1994). One of the key factors for abiotic stress in crop plants is the ill effect of global warming which may cause reduced precipitation, less snow pack, and earlier snow melt, leading to drought conditions. In addition about 20% of the world’s irrigated lands are affected by salinity (Zhu, 2001), a situation worsened by climate changes.

References   Abro, G. H. and Wright, D. J. 1989. Host plant preference and influence of different cabbage cultivars on the toxicity of abamectin and cypermethrin against Plutella xylostella. Ann. Appl. Biol. 115: 461-467. Adam, K. L. 2006. Squash bug and squash vine borer: organic controls. National Sustainable Agriculture Information Service. ATTRA Publication. Adan, A. P., Estal, D., Budia, F., Gonzalez, M. and Vinuela, E. 1996. Laboratory evaluation of the novel naturally derived compound Spinosad against Ceratitis capitata. Pestic. Sci., 48:261-268. Adetula, O and Denton, L. 2003. Performance of vegetative and yield accessions of cucumber (Cucumis sativa Linn.) Horticultural Society of Nigeria (HORTSON) Proceedings of 21st Annual Conference, 10-13 Nov, 2002. Aharoni, Y., Copel, A. and Fallik, E. 1993. Hinokitiol (â-thujaplicin), for postharvest decay control on ‘Galia’ melons. New Zealand Journal of Crop and Horticultural Science, 21(2): 165-169. Ahlawat, Y. S. and Kulshreshtha, U. K. 1977. A new graft transmissible disease of Sechium edule. Indian Phytopathology, 30:268-269. Ahmad, S., Brattsten, L. B., Mullin, C. A. and Yu, S. J. 1986. Enzymes involved in the metabolism of plant allelochemicals. In: L. B. Brattsten and S. Ahmad (Eds.), Molecular aspects of insect-plant associations. Plenum, New York, pp-346.