red hairy caterpillar

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Anthracnose disease of papaya

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The disease is prevalent wherever the papaya is grown and becomes more prominent after reaching the coumer. Symptoms The  on fruits first appear as brown superficial discolouration of the skin which develop into circular, slightly sunken areas and 1 to 3 cm in diameter. Gradually the lesions coalesce and sparse mycelial growth appears on the margins of the spots. Under humid conditions, an encrustation of salmon pink spores are released. Infection at early stages of fruit results in mummification and deformation. Necrotic spots are produced on the leaves and stems. Errupted acervuli in concentric rings are seen on the petioles. Although the disease usually appears on the ripening portion of the fruit, they occasionally infect its green portions first causing small lesions. Soon after penetration of the fungus, the latex from the fruit oozes out in sticky mounds of horns. Lesions enlarge very slowly and rarely larger than 12 mm in diameter as long as the fruit remains green. Fungi Gloesoporium papayae P. Henn. and Colletotrichum papayae (Syn. Colletotrichum gleosporioides Penz.). Mode of spread and survival The incipient infection is carried by the fruits from the field. The disease is spread through wind-borne conidia. Conidia are also spread by rain splashes. Epidemiology Severity of the disease on foliage is increased under conditions of excessive moisture. Old leaves are generally more susceptible. Lesions develop more slowly on the immature fruits than on the mature fruits

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Powdery mildew of papaya

Powdery mildew of papaya : 

Powdery mildew of papaya Symptoms Diffuse mats of external, white mycelium develop on both the leaf surfaces but are more common on the underside of the leaves. Lesioned areas become chlorotic and sometimes are surrounded by a dark margin. Production of conidia causes mycelial mats to appear powdery. Flower stalks and fruits are also affected. The fungus also attacks the stem of the young seedlings when grown under reduced light conditions. The typical powdery growth is found on the stem of the plant. Severe attack leads to death of top portion of the seedlings. Fungus Oidium caricae Noack. It is an obligated parasite. The mycelium is hyaline, septate and haustoria develop in epidermal cells. Conidia are hyaline, granular and 14 to 19 x 28 to 30 um.

FRUIT ROT OF PAPAYA : 

FRUIT ROT OF PAPAYA

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Fruit rots Rhizopus stolonifer (Fr.) Lind It occurs in different parts of India. The rot is characterized by production of irregular, water - soaked lesions. They gradually enlarge and are covered with white and dark brown fungal growth and sporangiophores. Finally the fruit collapses, becomes watery and emit a foul odour. The fungus infects wounds Fruit fly punctures after harvest increase the disease incidence. The rot rapidly destroys the entire fruit and quickly spreads to other fruits. To control the disease dip the fruits with DCNA (2,6-dichloro - 4 nitroaniline) at 1,000-2,000 ppm. Hot water treatment of fruits at 49 oC

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Ring spot of papaya

RING SPOT OF PAPAYA : 

RING SPOT OF PAPAYA The disease is characterized by vein clearing, puckering or bulging of the leaf tissues between the secondary veins and veinlets on the upper surface of the terminal leaves. The margins and distal parts of young leaves roll downwards and inwards. The virus induces mosaic mottling, dark green blisters, necrosis of chlorotic areas, leaf distortion which result in shoe-string symptoms and stunting of the plants. On the stem of young plants, mosaic or mottle symptoms also show dark green spots and oily or water-soaked streaks. The fruits are smaller, deeply lobed and lopsided and show circular and concentric rings. Diseased fruits contain low sugar content. Latex quality from diseased plants is poor. Causal agent Papaya Ring Spot Virus (PRSV) (Syn. Papaya distortion ring spot virus). The virus particles are rod shaped with 760 to 800 nm in length and 12 nm in width. Thermal inactivation point of the virus lies between 54 and 60 oC and it loses its infectivity at 10-3 dilution. The virus is viable upto 10 hours at 27 to 30 oC

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Stem rot of papaya

Water soaked patches appear on the stem at the ground level. These patches enlarge and girdle the base of the stem. The diseased tissues turn dark brown or black and rot. The terminal leaves turn yellow, droop and wilt. Fruits shrivelled and drop off. Due to disintegration of parenchymatous tissues at the bse of the stem the entire plant topples over and dies. If the back is opened the internal tissues appear dry and give a honey comb appearance. Rotting may spread above and below on the stem and down to the roots. The roots deteriorate and may be destroyed. Fungi Pythium aphanidermatum (Eds.) Fitz. and Rhizoctonia solani Kuhn : 

Water soaked patches appear on the stem at the ground level. These patches enlarge and girdle the base of the stem. The diseased tissues turn dark brown or black and rot. The terminal leaves turn yellow, droop and wilt. Fruits shrivelled and drop off. Due to disintegration of parenchymatous tissues at the bse of the stem the entire plant topples over and dies. If the back is opened the internal tissues appear dry and give a honey comb appearance. Rotting may spread above and below on the stem and down to the roots. The roots deteriorate and may be destroyed. Fungi Pythium aphanidermatum (Eds.) Fitz. and Rhizoctonia solani Kuhn

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Mosaic of papaya

Mosaic disease of papaya : 

Mosaic disease of papaya Mosaic It is noticed in Bolivia, India, Peru, the U.S.A. and Venezuela. The mosaic disease was first reported in India from Mumbai and Pune in 1947. It is prevalent in Andhra Pradesh, Bihar, Karnataka Madhya Pradesh, Maharashtra, Orissa, Punjab, Rajasthan, Utter Pradesh and West-Bengal. This disease may cause as much as 90 per cent damage in severe cases. Symptoms The disease produces typical mosaic symptoms showing chlorosis with dark green blisters on the leaves. The lamina is reduced and malformed. The stem, petiole and fruits develop enlongated water-soaked areas showing concentric or circular rings or lesions. The diseased plants show decline and marked reduction in growth. As the disease advances, older leaves fall down and a small tuft of younger leaves is left at the top which are also malformed and have typical mosaic symptoms. Diseased plants of fruits develop innumerable circular, water-soaked lesions with spots in the centre. In severe cases, the fruit size is severely reduced with deformed shape. There is no reduction in the flow of latex. Fungus Oidium caricae Noack. It is an obligated parasite. The mycelium is hyaline, septate and haustoria develop in epidermal cells. Conidia are hyaline, granular and 14 to 19 x 28 to 30 um

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Leaf spot of papaya

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Symptoms The disease is characterised by severe curling, crinkling and distortion of the leaves accompanied by vein clearing and reduction of leaf lamina. The leaf margins are rolled downward and inward in the form of inverted cap. The veins get thickened and turn dark green. The leaves become leathery and brittle and petioles are twisted. Affected plants bear only a few flowers and fruits. In advanced stages, defoliation takes place and growth Leaf curl of papaya