PEST AND DISEASE MANAGEMENT IN GUAVA

By Omprakash kumar singh

Bsh-09-039

INTRODUCTIONGuava is hardy, aggressive, and a perennial tree that has recently become a cultivated crop of subtropical regions. It is scientifically Psidium guajava and belongs to the family Myrtaceae.

Guava trees are seriously damaged by the citrus flat mite.The guava tree is attacked by 80 insect species, including 3 bark-eating caterpillars and the guava scale in India, but this and other scale insects are generally kept under control by their natural enemies.

Some important pests and diseases

Pests•Tea mosquito bug•Aphids•Mealy bugs•Fruit fly•Guava shoot borer•Guava weevil•Thrips, etc.

Diseases•Wilt•Red rust•Anthracnose•Canker•Phytophthora fruit rot•Dry rot•Damping off

Wilt: Fusarium oxysporum f.sp. psidii

Symptoms1.Yellowing of leaves2.Drowsiness with yellow to reddish discoloration3.Bare and dry twigs4.Hard, underdeveloped, stony fruits5.Entire plant defoliated and dead within 15 days from full wilting upto 1 year in some cases

Management 1.Cultural method- clean cultivation i.e., uproot wilted tree, timely and adequate manuring2.Chemical method- injection of 0.1% water soluble 8 quinolinol sulphate. It provide protection for 1 year in disease affected area.

Other wilt causing agents areRhizactonia bataticola

Macrophomina phaseolinaFusarium solani

Gloeosporium psidii

Anthracnose: Colletotrichum psidii

SymptomsPinhead spots on unripe fruits that are dark brown in color, sunken, circular.Creamy spore masses in moist weather.Unripe fruit become corky and harder and develops cracks.Leaves have necrotic lesions on the margin and tip

• Management • Resistant variety like apple

guava are used In affected area.

• Sprays of Bordeaux mixture at 7 day interval

• COC and cuprous oxide are also significant in controlling the disease

• Monthly spray of Difolatan(0.3%) closely followed by Dithane Z-78(0.2%) is effective

Canker: Pestalonia psidii

• Symptoms1. Occur on green fruitsAppearance of minute ,

circular , necrotic area with elevated margins.

2. Fruits underdeveloped, become hard, malformed and mummified and drop in large numbers

• Management1% Bordeaux mixture or

lime sulphur at 15 day interval.

Use of canker resistant cultivar like Safeda and Apple colour.

Leaf extracts of Neem and Tulsi (Azadirachta indica and Ocimum sanctum respectively) inhibit spore germination.

Guava rust: Puccinia psidii

• symptoms• The pathogen can affect

foliage, young shoots, inflorescences and fruit of guava.

• Typical symptoms associated with this disease include distortion, defoliation, reduced growth and if severe, mortality.

• On fully expanded leaves, dark bordered, roughly circular brown lesions with yellow halos develop

• Management• Control of guava rust is

based on the use of fungicides.

• Scouting fields for onset of disease or during the times of year when environmental conditions are favorable for pathogen infection are recommended so that proper and timely fungicide applications can be made.

Guava rust

. Algal leaf spot: Cephaleuros virescens

• Symptoms• Disease symptoms are exhibited

on both abaxial and adaxial leaf surfaces as orange, rust-colored, dense silky tufts ranging from 5 to 8 mm in diameter.

• Upon scraping away these spots, a thin, grayish white to dark-colored, necrotic crust remains on the leaf.

• Management• Algal leaf spot can be reduced by

maintaining tree vigor with cultural techniques such as proper fertilization and irrigation, proper pruning to enhance air circulation within the canopy and sunlight penetration, managing weeds and wider tree spacing.

• Managing insect, mite and other foliar diseases increases tree vigor and lessens susceptibility to this disease.

• Spray Copper oxychloride 0.25%.

Leaf spot symptoms

Damping off: Rhizoctinia solani

• Pre emergence – infected seeds and seedlings show soaked discoloration

• Post emergence –hypocotyl is discolored into yellowish to brown and later turn soft and constricted.

• Such seedlings ultimately toople over and die

Management•Seedling treated with Bavistin @ 3g/Kg seed controls the disease quite effectively

Tea mosquito bug• Control1. Spray Endosulfan 35 EC at

the rate of 2 ml/lit or alathion 50 EC at the rate of 1 ml/lit or Monocrotophos 36 WSC @ 2ml/lit or neem oil 3 %.

2. Spraying should be done in early mornings or late evenings, at least four times at 21 days interval during fruiting season.

Aphids

ControlSpray Monocrotophos 36 WSC @ 1ml/lit or Dimethoate 30 EC @ 2 ml/lit to control aphids.

Mealy bugsControl1.The mealy bugs can be controlled by spraying Triazophos @ 2ml/lit + neem oil 5 ml or phosalone 0.05% + neem oil 5 ml.2.Release of Cryptolaemus montrouzieri beetles (Coccinellid beetles) @ 10 beetles /tree is also recommended.

Fruit flyControl1.Remove the fallen fruits and bury them deeply with Lindane 1.3% dusted over them. 2.Spray Endosulfan 35 EC or Malathion 50 EC @ 1 ml/lit four times at 15 days interval. 3.Stir the soil around the tree during pest incidence and dust Lindane 1.3%. 4. Use polythene bags fish meal trap with 5 gm of wet fish meal + 1 ml. dichlorvos in cotton.5. 50 traps are required/ha, fish meal and Dichlorvos soaked cotton are to be renewed once in 20 and 7 days respectively.

Thank you