Thanks for the other contributions re vines and control of PM. Does anyone have experience with Strike rust control in wheat using CT. What might be the required Fungi/bacterial range to control strike rust, any help would be appreciated. Following are results from a trial of CT this year. Comments re the conclusions would be appreciated.
Compost Tea Trial Preliminary results from Trial of Compost tea for control of Powdery Mildew in Cabernet Sauvignon and Shiraz Grapes, Redmond Western Australia. This area is considered a high risk area for PM and Botrytis.Lower risk are Downy mildew Phomopsis and Esca. Introduction A trial was done to examine the effectiveness of Compost Tea (CT) in controlling PM and Botrytis. At the beginning of the trial it was agreed that regular monitoring of disease levels would be done and control measures adjusted as necessary to ensure minimal risk to the crop. The entire area of vines was sprayed no control area was left unsprayed. The vineyard contains 2 varieties Shiraz and Cabernet Sauvignon. The CT used was tested at SFI Australia and showed high numbers of fungi (active and total biomass) with bacteria in good range. Test results available at www.composttea.com.au Compost tea (CT) was applied at 70 litres per ha using an air-assisted sprayer. Pressures were kept under 4 bar. No spreader sticker was used. The vineyard was a young vineyard that had had a good history of PM control from the previous year. Trial area was 7 ha. CT was sprayed on 28/09/02 22 days later on 22/10/02, 8 days later on 30/10/02 14 days later on 14/11/02, 14 days later 28/11/02 7 days later on 05/12/02 14 days later on 19/12/02, 14 days later 03/01/03, when due for CT the grower discovered 1% of 1% of bunches in the vineyard had Powdery mildew on them. It was noted that no Powdery was found on any of the Shiraz grapevines.The recommended spray interval was 7 days between CT sprays. The actual time between sprays was 13 days. The grower made a decision to spray the entire vineyard with sulphur to control the powdery as this suited his spraying regime. It was noted by the grower and myself that we had made an error in application of the CT. The grower was diligent in picking up the CT early in the morning to spray in the cool of the morning however we realised afterwards that the last of the spray was going out in the middle of the day. This would result in damage to the Microorganisms due to UV radiation etc. This was particularly significant since the area that was sprayed last, (at midday usually), was the area where the outbreak occurred. Conclusion From the start of spraying CT at the end of September to the start of Jan 2003 there has been only CT applied to control PM. Other materials applied were Fish and Kelp between some of the CT sprays. So for 3 plus months the vineyard was completely clean using only CT. Reasons for small outbreak - Spray interval too wide. 13 days was the average, this is too far apart. 7 days apart is indicated. - Spraying organisms out in the middle of the day is likely to have reduced colonisation.
The grower was pleased with the result and is planning to continue CT applications after Verasion (berry softening). Regards
Mike Harvey.
New Life Soils, RMB 630 Kendenup WA
6323.
Ph 98514393 Fax 98514693 Mob 0427
514393.
Email mharvey@westnet.com.au
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