Recommendations for Apple diseases during May and June

Solan, May 27 

Farmers in the apple growing areas need to be vigilant, as due to the rains in the first fortnight of May, high humidity conditions are prevailing in the state which makes it congenial for the spread of apple scab and other foliar diseases. The Department of Plant Pathology of Dr YS Parmar University of Horticulture and Forestry(UHF), Nauni had proposed to organize 24 group meetings of farmers in the apple growing districts of the state to create awareness about the disease management approaches for the management of diseases in apple crop. Due to the imposition of Corona curfew, the process has been halted, but the University has created two Whatsapp Groups, one of representative farmers and another of Horticulture Extension Officers from the different districts to communicate the advisory for the farmers to be followed during May-June, 2021. As the apple fruit is in the development stage, the farmers need to adopt the following recommendations as per the Spray Schedule recommended for the year 2021:

When the fruit is of walnut size:

· The sprays of mancozeb @ 0.3% (600gm / 200L water) or propineb @ 0.3% (600gm / 200L water) or dodine @ 0.075% (150gm / 200L water) are recommended for the management of apple scab.

· Metiram 55% + pyraclostrobin 5% WG @ 0.1% (200gm / 200L water) or tebuconazole 8% + captan 32% SC@ 0.25% (500ml / 200L water) or fluxapyroxad 250g/l + pyraclostrobin 250g/l 500SC @ 0.01% (20ml / 200L water) are recommended for the management of premature leaf fall and Alternaria leaf spot in apple.

During fruit development (20 days after 4th spray)

· The sprays of propineb @ 0.3% (600gm/ 200L water) or zineb @ 0.3% (600gm / 200L water)are recommended for the management of apple scab.

· Tebuconazole 50% + trifloxystrobin 25% WG @ 0.04% (80gm/ 200L water) is recommended for the management of premature leaf fall.

· Carbendazim 25% + flusilazole 12.5% SC @ 0.08%(160ml/ 200L water) is recommended for the management of premature leaf fall and Alternaria leaf spot in apple.

This year, two new fungicides namely Cursor 40%EC (flusilazole 40%EC@ 0.025%) (50ml/200L water) for apple scab at petal fall/ pea stage, and Lustre 37.5% SE (carbendazim 25% + flusilazole 12.5% SE@0.08% (160ml / 200L water) for premature leaf fall and Alternaria leaf spot at petal fall/ pea stage and fruit development (20 days after 4th spray) have been added after evaluation. Flusilazole is a fungicide with curative and preventative activity. It is a potent inhibitor of sporidial growth and acts by inhibiting ergosterol biosynthesis through direct inhibition of the 14α‐demethylation of ergosterol precursors.Carbendazim is a broad-spectrum systemic fungicide with protective and curative action. It is taken and translocated within the plant as a result of which the latter become fungitoxic. It mainly acts by inhibiting development of germ tubes, the formation of appressoria and the growth of mycelia. The use of new combinations of fungicides exhibits systemic activity, provides protectant, curative and eradicant control, andboth the fungicides in these combinations have different modes of action. Therefore, such a new combination can delay or prevent the build-up of resistance in the pathogen and can be effectively utilized as a promising preventive fungicide for the control of apple diseases.

The university also receives queries from farmers regarding mixing of different insecticides/fungicides with fertilizers. The scientists from the department of Plant pathology do not recommend these as it can create an adverse impact on plants. The university has advised farmers to email their queries regarding different diseases with 5-6 representative photos to hodmpp@yspuniversity.ac.in or hodmpp2014@gmail.com so that these can be addressed by the department.