India is the second largest producer of vegetablesafter China.
Our country has 10.295 Mha of its area under vegetable cultivationowing to a production of 176.17 Mt with a productivity of 17.11t/ha (National HorticultureDatabase 2016). Insect pests are one of the biotic factors which hinder thevegetable production in India. Apart from direct damages, they also act asvectors of many diseases. In vegetables, the crop loss due to sucking pests isto the tune of 30-40 percent (Rai et.al 2014).
These insects suck the sap from leaves, fruits, flowers and cause unevenripening and underdevelopment. The control of sucking pests is difficultbecause they have high fecundity. Inorder to protect crops from pests, adverseclimatic conditions and to reduce dependency on frequent pesticide use,protected cultivation practices are widely adopted in many parts of the worldincluding India.
But these protected structures have limitations, particularlywith small insect pests which can easily enter through the physical screensprovided. Very small mesh size in nets may hinder natural ventilation of thestructures.Inorder to curb insect activity, farmers use a widearray of insecticides belonging to different classes. Even though chemicalcontrol is the primary method to control the sucking pests, it has not beenfound effective or fails because of rapid selection of resistant pest biotypesof whitefly (Cahill et.al 1995,Denholm et.al 1996), thrips(Epsinosa et al 2002), or aphids (Foster et al 2000). Botanicals like neem can beefficient with low risk of resistance selection (Thoeming et al.
2003, Kumar et al.2005) but suffer from rapid dissipation and degradation in tropical conditionswhich reduces its persistency(Barrek etal. 2004). So, the need of the hour is to shift to eco-friendly butsustainable methods of pest management.
Biointensive pest management (BIPM) is essentiallya component of IPM which will help to reduce dependence on chemical pesticidesand ecological deterioration. BIPM includes biopesticides derived frommicrobials, parasitoids, predators, botanicals and all non-conventional methodsof pest control (Dhandapani,N. 2003).In India, tomato (Lycopersicon esculentum) is one of the most consumed vegetablecrops. Tomato ranks third in priority after potato and onion in India. Indiaranks second in the area as well as production of tomato. It is cultivated onan area of 799M ha with a production of 19.
54 Mt (National Horticulture Board2016-2017 database). Tomato production under protected cultivation in thetropics is extremely vulnerable to abiotic stresses(temperature,humidity,airflow etc) (Ajwanget al.2002) and to biotic stresses represented by insects (whitefly,thrips, aphids) and plant virus diseases vectored by these insects. (Throngit et al. 1986, Premchandra et al. 2005). The damage that whiteflycauses on host palnts results from sap sucking, heavy deposition of honeydew,plant disorders such as uneven ripening (Schuster et al. 1990) and spread diseases caused by different kinds ofGemini viruses (Brown et al.
1995).Thrips cause mechanical damage through feeding and oviposition and indirectlyby transmitting tospo viruses ( Premachandra et al. 2005).
Aphids ( Myzuspersicae) are another pest group causing direct damage by sucking plant sapand reducing overall quality and productivity. Often plants are attacked bycomplex of these pests, which can lead to detrimental infections by more thanone type of virus. (Summers et al.2004).Sticky traps- yellow, blue and silver are used tomonitor and control sucking pest populations in green houses as well as in openfield conditions. Yellow sticky traps suppressed whitefly populations, and maybe used to detect the first invasion and monitor populations of the greenhouse whitefly(Gillespie 1987).
Blue sticky traps (458-nm peak reflectance) were found moreefficient in catching thrips (Vernon and Gillespie 1990).Entomopathogenic fungi such as Beauveria bassiana, Metarhizium anisopliae, Lecanicillium lecani arebeing used for the control of sucking pests. They produce a variety ofextracelluar enzymes which can degrade the insect cuticle once they come incontact with insect body (Cooper et al 1987).Botanical pesticides are also in use in our countrysince a century to minimize losses by pests and diseases (Prakash et al.
1990).Azadirachtinis a natural biorational pesticide derived from neem tree. It is growthregulating, anti-feedant and repellant compound for phytophagous insects (Menkeand Gerhard, 2009). It delays or prevents moulting, reduces growth anddevelopment and oviposition and can cause significant mortality particularly inimmature (Coudreit et al. 1985,Prabhaker et al.1989). SimilarlyKaranjin oil from Pongamia are also used to control sucking pest populations inmany crops. Pongamia glabra commonly known as karanj is reported to be effectiveagainst insect pests of stored grains, field and plantation crops, andhousehold commodities.
More than 19 biologically active components have beenidentified from this plant. Oil, methanolic seed extract, acetone leaf extract,aqueous seed extract, chloroform seed extract and petroleum ether seed extractof karanj have been evaluated and found to act as oviposition deterrents, antifeedantsand larvicides against a wide range of insect pests. Karanj basedextracts/formulations have great potential for sustainable integrated pestmanagement programmes (Kumar et al.2012). Pongamiaoil reduced the survival rate of hoppers in rice (Mariappan et al 1988).Predators are also an integral part in pestmanagement tactics.
Green lace bug, Chrysoperlazastrowi sillemi, (Esben-Peterson) (Neuroptera- Chrysopidae) has long beenconsidered as an important natural predator because of its potential to controla variety of soft bodied insects like aphids, coccids, mealybugs, thrips,psyllids,whiteflies and eggs and larvae of many lepidopterous insects and mitesoccurring on various crops ( Rao and Satyanarayana, 1984). The larvae arepredatory in nature and the adults feed on pollen and netar. In order tomaintain the natural enemy population in the crop environment, banker plantscan be established.
Banker plants are self –contained sustainable system thatsupports non-pest prey species to support a continual source of natural enemiesthat disperse into the crop in search of other pests. The banker plants aremini-rearing system for the natural enemy. Growers see these plants as one wayof reducing the cost of bio-control agents (Matteoni )
