Mulberry is commercially grown in the country for its foliage to feed silkworms.
Leaf rust disease caused by a fungus reduces leaf yield as well as the leaf quality. The disease is prevalent during winter and monsoon seasons.
It starts progressing from 45 to 50 days after pruning and becomes severe on 70th day after pruning.
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Matured leaves are more prone to the attack and cause 10 – 15 per cent leaf yield loss.
Colour change
The infestation is first noticed as a circular pinhead sized brown eruptive lesion on the leaf surface. Later the leaves turn yellow in colour and fall off.
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The disease is spread through irrigation water and wind. Temperature ranging from 22-26 degree celsius and high relative humidity above 70 per cent are ideal for the disease development.
Control measures:
Follow wider spacing of plantation [90 cm x 90 cm or paired row planting system (150cm + 90cm x 60 cm)].
Avoid delay in harvesting the leaves
Spray 0.2 per cent Kavach (Chlorothalonil 75 per cent WP) on the leaves.
An acres requirement
About 150 litres of spray solution is required for one acre of mulberry garden.
The spray needs to be done 40-45 days after pruning/leaf harvesting during early morning or late evening.
Second spray
If the disease is not controlled a second spray is recommended after 10-15 days of first spray.
The fungicide sprayed leaves can be fed to the silkworms after four days.
(Dr. N. B. Chowdary, Scientist, Central Silk Board, Giddalur– 523357, Prakasam District, Andhra Pradesh and Dr. Satyanarayana Raju, Scientist, Regional Sericultural Research Station, Central Silk Board, Anantapuramu, Andhra Pradesh, Tamil Nadu, email: recsugid@gmail.com, Mobile: 08520882624.)