1 March 1996

NIP IN BUD FOR BEAN RUST PAYS

LAST year may have been unusual in terms of bean diseases, but it threw up some useful pointers in the Velcourt trials at George Farm, Stamford, Lincs, nonetheless.

Chocolate spot was a non-event in field beans. "It was the first year we havent had chocolate spot. But it was a really bad one for rust, especially in spring beans," reports technical director Keith Norman.

Ascochyta was also present, the winter variety Delta being most affected with up to 40% of the leaf area infected in March. But dry weather checked the diseases progress as the stems extended.

On spring beans 0.75litre/ha (0.5pts/acre) of Corbel (fenpropimorph) applied at the beginning of July "to nip rust in the bud worked wonders" producing nearly 1t/ha (8cwt/acre) of extra yield, he says.

But drought hit the spring beans badly leaving gross margins about £150/ha (£61/acre) less than for the winter crop.

Of the spring-sown varieties Victor, Spear and Mars emerged first and were more vigorous than others. The result seems directly linked to their higher thousand grain weight, notes Mr Norman.

White-flowered types Amazon, Caspar and Vasco appeared more affected by drought than other varieties.