Insect-pests management in arid and semi-arid horticultural crops

Abstract

In India, nearly 3, 17,090 sq km area falls under arid region, of which 70, 300 sq km is classified as cold arid and remaining is under hot arid region. About 61% of total hot arid area lies in Rajasthan. Arid and semi-arid horticultural crops are becoming popular for nutritional and health security as they are excellent sources of minerals, vitamins, antioxidants and photochemical. Among the horticultural crops, ber (Ziziphus mauritiana), date palm (Phoenix dactylifera), lasoda (Cordia myxa), aonla (Emblica officinalis), bael (Aegle marmelos), jamun (Syzygium cumini), pomegranate (Punica granatum), khejri (Prosopis cineraria) and cucurbit are the main crops of arid and semi-arid parts of the country. There are many reasons for low productivity of the arid and semi-arid horticultural crops. Hot arid region are marked by abiotic limitations such as high temperature, high potential evapo-transpiration, low erratic rainfall, low soil fertility, poor quality of ground water, etc., which lead to poor crop growth and yield. Apart from the climatic limitations, the biotic factors like pests and diseases are also one of the limiting factors for crop production in arid and semi-arid ecosystem. The major pests of this area ber fruit fly, Carpomyia vesuviana; ber stone weevil, Aubeus himalayanus; fruit borers; aphids; thrips; lemon butter fly; datepalm scale, Parlatoria blanchardi; fruity fly, Bactrocera cucurbitae; leaf miner, Liriomyza trifolii; pod borer, Helicoverpa armigera; white flies, Bemisia tabaci; thrips, Frankliniella occidentalis; shoot and fruit borer, Leucinodes orbonalis; Hadda beetle, Epilachna viginctioctopunctata; aphids, Aphis gossypii and ash weevil, Myllocerus subfasciatus are major constraints which causing the considerable economic loss and increasing the cost of arid and semi-arid horticultural crops production of rain fed farmers. Ber fruit fly (Carpomyia vesuviana) is the most destructive pest of ber. It contributing towards low yield and poor quality of fruits and it caused yield loss up to 80% under severe infestation. The severe incidence of fruit weevil (Aubeus himalayanus) has been recorded in arid region that caused considerable damage to ber fruit on Gola (28.8 %) and Seb (51.8 %) from tree sample and Gola (74.10) and Seb (89.80) in fallen fruits. In date palm, the scales, Parlatoria blanchardi and lesser date moth, Batrachedra amydraula are an important pests of date palm infesting leaves and fruits. The incidence of scale insect was found 6.46 per cm2 of leaves and incidence of lesser date moth was around 16 to 20 %. Therefore, the highest fruit damage was recorded in the varieties Medjool (16.01%) followed by Khalas (14.54%) and Nagal (13.78%), whereas, lowest fruit damage was recorded in the varieties Zagloul, Medini and Zahidi as 1.43, 1.51 and 2.30 per cent due to lesser date moth. The cucurbit fruit fly (B. cucurbitae) has been the most prominent pest over the last several decades in India. Depending on the environmental conditions and susceptibility of the crop species, the extent of losses varies between 30 to 100%. The field experiments on assessment of losses caused by cucurbit fruit fly in different cucurbits been reported 28.7 - 59.2, 24.7 - 40.0, 27.3 - 49.3, 19.4 - 22.1, and 0 - 26.2% yield losses in pumpkin, bitter gourd, bottle gourd, cucumber, and sponge gourd, respectively. Considering previously reported, it is apparent that >50% of the cucurbits are either partially or totally damaged by fruit flies and are unsuitable for human consumption.