Dwindling pgrs bring bigger lodging risks

8 May 1998




Dwindling pgrs bring bigger lodging risks

By Andrew Blake

SEVERE shortages of late plant growth regulators are combining with delayed spray applications to create the worst lodging risk in cereals for years.

Bad weather following rapid, early spring growth means 20-30% of wheats and barleys received no initial regulator. Without some lodging protection yield and quality in many may be in jeopardy, especially where anti-eyespot sprays were also missed, says Hutchinsons Dick Neale.

The dilemma for many growers is that most crops are beyond the third node detectable (GS33) stage at which even 5C chlormequat products may legally and safely be applied.

Sources of alternatives have almost dried up. Ethephon-based Cerone and Terpal are virtually sold out, says Dalgetys Peter Corbett. "Supplies are tight all over Europe for the same reasons as here."

Rhone Poulencs David James expects further imports of Cerone next week. But BASFs John Bedford says the company cannot simply turn on the tap to increase the flow of Terpal. Moddus is also very tight, admits Andy Cottrell for supplier Novartis.

Making the most of limited supplies demands careful crop inspection, with limited quantities of later materials, such as Cerone and Terpal (both ethephon-based), and Moddus best used on crops at most lodging risk and most likely to give an economic response, notes Mr Neale.

Variety straw strength and field history are the main factors to take into account, he explains.

One danger is that some crops formerly felt to be at risk may be at less risk now, having had nitrogen dressings delayed by the same poor conditions which prevented spraying, he notes. "I would hate to see people reacting with high rates of growth regulator on stressed crops."

Modern fungicides able to protect the increased yield potential from chlormequat mean late application may not cause the damage once experienced, suggests Brown Butlins David Stormonth. "But once you get past GS32 there are no tangible benefits."

Economies can be made on label rates of later materials, provided an integrated approach is adopted, he says. "The minimum dose of Terpal for an effective lodging response is 0.75 litres/ha. But if you are looking for just necking control you could go to 0.5 litres."

Moddus (trinexapac-ethyl) could be helpful where crops have not yet reached flag-leaf emerged (GS39), according to Novartiss Mike Pearson who says new supplies are on their way from the Continent. "But it is not a late product." Applications beyond that point could lead to blind grain sites, he warns.

One option for eking out supplies of Cerone up to flag-leaf emerging (GS37) is to use it at 0.3 litres/ha in a mix with 0.8 litres/ha of Adjust (chlormequat), maintains Dalgetys technical manager Bob Bulmer.

Other possible alternatives include Sypex and Upgrade (both chlormequat + 2-chlorohphosphonic acid), though the former is available only through selected distributors, notes BASFs Lance Middleton.

Whatever the choice, Mr Neale reminds growers that regulator use outside label advice can risk losing markets. "Under crop assurance, and even without crop assurance, the grain could be condemned."

LATE CEREAL PGR

&#8226 Product supplies tight.

&#8226 Chlormequat cut-off near or past.

&#8226 Crop assessment vital.

&#8226 Economies possible.

&#8226 Grain assurance risk.

LATE CEREAL PGR

&#8226 Product supplies tight.

&#8226 Chlormequat cut-off near or past.

&#8226 Crop assessment vital.

&#8226 Economies possible.

&#8226 Grain assurance risk.


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