Submitted by spsarathy
S. Parthasarathy, Ph.D Scholar, Dept. of Plant Pathology, CPPS, TNAU, Coimbatore
The Mango (Mangifera indica L.), belongs to the dicotyledonous family (Anacardiaceae), in the order Sapindales, is one of the world’s most important and reputable fruits and is considered as the “King of fruits” or “Apple of tropics”, probably originated from Indo Burma region and thus has prominent position among commercial fruits grown in India. Konkan region of Maharashtra is famous for a leading variety ‘Alphonso’, which alone occupies about 1.70 lakh hectare area under single variety. The economy of this region is mainly dependent on the mango crop. Also, Dharmapuri, Krishnagiri, Salem and Theni districts of Tamil Nadu was most famous for the production of pulpy mango varieties. The warm and humid climate of this region is most congenial for development of pests and disease. The success of mango crop is associated with how effectively pest and diseases are managed. Therefore, mango growers are very much concerned about crop protection. They indiscriminately apply whatever pesticides that is available in market. This has resulted in development of resistance to pesticides and resurgence of secondary pests like flower midge, thrips, scale insects and mealy bugs. Earlier, the infestation by mango hoppers was considered as a major problem and the plant protection measures were concentrated on these single pests. Twenty two species of mango hoppers were reported to be feeding on mango.
Out of these, only three species were economically important earlier; only Amritodus atkinsoni was the predominant species. However, since 1985, Idioscopus neveosparsus has become number one and more serious during flowering period. The nymphs and adults suck the sap from tender shoots, leaves, inflorescence and even tender fruits.
However, the infestation was more severe during flowering, causing severe flower and fruit drop. Apart from the feeding injury, they also secrete honeydew like substance which invites the problem of black sooty mould. It hinders the photosynthetic activity of the plant and deteriorates the fruit quality. Such types of fruits fetch less price in the market. Losses to the extent of 60 per cent are reported.
Now the pest scenario has changed. Apart from mango hoppers, considerable increase in midge fly, Erosomyia indica intensity was noticed since last decade. The blossom midge which was noticed on private orchard during 1985, is now posing serious threat in mango production. This pest was first noticed in India at Coimbatore region in 1964 and later on reported all over the country. The outbreak was observed on vegetative flush of July-August.
However, severe incidence was observed during December-January on inflorescence and as well as on vegetative shoots. Female fly lay eggs on tender shoots vegetative buds, leaf and panicle rachis. Larvae feed internally on tissues and thus develop galls. The galls finally turn black. In severe cases, affected shoots/panicles will partially dry up. Incidence on inflorescence leads to fruit drop. Now incidence is also noticed on small fruits resulting in fruit drop.
Integrated Pest Management for Mango
Removal and destruction of affected and fallen fruits due to fruit fly and fruit borer infestation Destruction of affected shoots due to shoot borer infestation along with larvae in young orchards. Remove the dead and weak branches in order to reduce the inoculum of various pathogens. Keep the stalks of the fruit clear by removing dried rachis, small leaves which harbor the disease and pests inoculums. Remove the unfruited panicles to avoid scratching injury to fruits, put dried leaves in between adjacent fruits. Ploughing/weeding or digging of the soil under tree canopy. This will expose the hibernating pupae of gall midge and other pests like fruit borer, fruit fly etc. Avoiding overcrowding of the laterals and foliage as it develops the favourable microclimate for pest and disease build up. It also prevents the penetration of the pesticide sprays which invites the pest resurgence due to residual population. Therefore, proper thinning/centre opening should be done and trees be kept open and well aerated.
The neem products particularly Nimbicidine @ 2 ml/lit can control 50 to 60% hopper population and hence it can be used during lean periods of outbreak right from the bud burst stage and thereafter in 10 to 15 days interval, so that hopper build up will be checked without disturbing natural enemies like red ants, spiders and lace wing bugs and coccinellids which are common predators in mango garden.
For blossom protection, use 3 ml Cypermethrin 25 EC or 5ml Fenvalerate 20 EC or 9ml Decamethrin 2.8 EC or 20ml Quinalphos 25 EC or 3ml Imidacloprid 17.8 SL or 1.2 g Clothianidine 50 WDG or 1.0 g Thiomethoxam 25 WDG or 20 ml Phenthoate 50 EC or 10 ml Dimethoate 30 EC per 10 lit of water.
Midge : Fenitrothion (0.05%) Thirps : Dimethoate (0.03%) or Phosalone (0.05%) if intensity is more apply Thiomethoxam 25% 2gm or Spinosad 45% 2.5 ml/10 lit. Mealy bugs : Monocrotophos (0.05%) for early outbreak and DDVP (0.05%) during advance stage of fruit development
Shoot borer: Quinalphos or Monocrotophos (0.05%) The trees and branches when cut, invites the stem borer problem. Therefore, cut portions should be treated with pesticide and applied with Bordeaux mixture
Glyricidia is a major host of mealy bugs, Ferissia virgata which is predominant species of mealy bugs in Konkan region. The incidence was noticed in the month of March. Therefore, the population of mealy bugs on glyricidia should be monitored form March onwards and if noticed, glyricidia stumps should be chopped off and destroyed. Explore the possibility of releasing, Cryptolemus montrizerae, a potential predator of mealy bugs during second fortnight of March as spray schedule will already be exhausted by this time and hence, there is no hurdle in establishment of predator population.