Crop Care – Fortress– Technote Page 1 TN09-22FOR-H

CONTROL OF WHITE ROT IN ONIONS Fortress has been shown over a number of years to be highly effective against white rot in onions and garlic. Fortress 500 contains 500 g/L of procymidone formulated as an easy to use suspension concentrate. WHITE ROT IN ONIONS The disease, white rot of onions is caused by a soil-borne fungus, Sclerotium cepivorum . This fungus attacks the below ground parts of onion plants at any time throughout the season when environmental conditions are favourable. Crops planted late autumn to early winter are the most susceptible to infection. Cool wet growth conditions provide white rot the best chance to cause economic damage to onions. The potential yield loss can be 100% in bad infections. What makes white rot such an insidious disease is its persistence in the soil. The sclerotes (or resting bodies of the fungus) can survive in the soil for more than ten years even if onions are not grown. The disease is easily spread by machinery, pickers or soil movement by flood water. The disease is often worst where flood waters peak. CONTROL OF WHITE ROT WITH FORTRESS 500 FUNGICIDE Fortress is a systemic and protectant fungicide and controls white rot by acting as a disinfectant stopping the fungus from growing and infecting the plant. The systemic activity of Fortress 500 has some curative effect on established root infections. Control with Fortress 500 depends on the correct use of a combination of seed treatment with a soil spray programme. The seed treatment provides early season disease control while the soil surface spray programme provides longer term control through the season.

Seed Treatment

Add 20 mL of Fortress 500 to the seed and mix thoroughly until seeds are wet.

Spread the seed and allow to dry. Sow within 14 days of treatment.

NOTE: Seed treatment should be used in conjunction with soil applications to achieve satisfactory control of white rot. CAUTION: Treated seed may germinate poorly in cold, wet soil. Where these conditions are likely to occur, use a soil treatment only or consider an increased seeding rate. Soil Surface Spray

Use 2 L/ha in a minimum of 250 L water Apply to soil surface just after sowing

and repeat 10 weeks later. A further soil surface spray of 2 L/ha

may be necessary if frequent or extended periods of cool moist conditions occur later in the season.

NOTE: Do not spray directly over exposed seed in furrows before covering with soil. WARNING: Soil persistence of Fortress 500 can be reduced under alkaline soil conditions.

Fortress is a registered trademark of Crop Care Australasia Pty Ltd. This publication is a guide only and not substitute for professional or expert advice. The product label should be consulted before use of any of the products referred to in this publication. Crop Care Australasia Pty Ltd shall not be liable for any results, loss or damage whatsoever, whether consequential or otherwise through the use or application of products and / or materials referred to herein. Before using, always read the product label. Contact your local Crop Care distributor for further information: Customer Service Australia Wide: 1800 111 454 II Fax: 07 3909 2040 II www.cropcare.com.au