South: Hot weather ups brown rust risk

England 2, Germany 2, it should have been. Rain in June, we should have had. Neither of the two events happened and that means England come back and wait for another four years. We shall have to wait for one year and hopefully rains will come at the right time next year. The light chalky soils in Hampshire and Wiltshire have suffered badly from lack of water over the last three to four weeks and I fear that it is going to be only an average harvest.

All cereal crops are at grain filling stage (GS69 +). With the current hot weather, there is serious a risk of brown rust on the susceptible varieties of wheat and spring barley. Carefully monitor fields where the T3 fungicide was missed or a less than robust rate was used at the T2 timing. Infections of brown rust even at this late stage can lead to a yield reduction of up to 25%.

Weed control, especially grassweed control has been difficult this year due to the cold weather early in the season and then exceptionally dry weather since April. Herbicides need growing conditions to work effectively. However it is also possible that resistance to the grassweed herbicide is an issue.

It is a good time now to map fields for any areas where an unusually high number of grass weeds are present or weeds appear where otherwise not normally seen. Grass seed samples should be taken from mid July onwards, making sure the seed is mature. The seed is mature when the seed falls off the seed head when shaken and should not have to be peeled off.

Unusually late, spring bean variety Fuego is showing symptoms of downy mildew, usually seen as a felt-like grey brown growth on the underside of the leaf and yellowing on the top surface. This is a devastating disease which can lead to a serious loss of yield. Spray Folio Gold (chlorthalonil + metalaxyl) as soon as symptoms are noticed.

Oilseed rape crops will be ready for desiccation in about a fortnight. Glyphosate will be the favourite material to use in non-weedy crops. Add Transcend to glyphosate to reduce seed loss from pod shatter. In weedy fields use either Reglone (diquat) or Harvest (glufosinate ammonium).

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