CROP MONITOR

High rejection rates due to pink grain despite low fusarium Incidence at GS 73

Provisional results from the Defra crop monitoring project for 2004 showed that across England the incidence of fusarium ear blight (FEB) was lower than the 10 year mean with only 2001 having lower levels in the last 7 years.

The predominant species isolated was Fusarium langsethiae followed by F. graminearum and F. poae. F. langsethiae is a newly described Fusarium species which causes a discrete lesion on the glume similar to that caused by F. poae. As a result it is unlikely to have a dramatic effect on yield, however it does produce the type A trichothecenes mycotoxins T-2 and HT-2.

As in 2002 and 2003, levels of F. graminearum continued to be higher than F. culmorum. Worldwide F. graminearum is probably the most important Fusarium species in terms of yield loss and mycotoxin contamination of grain. F. graminearum was primarily found in the East and South West.

The effects on yield and quality due to Fusarium species are likely to be lower than in previous seasons due to the low incidence of FEB and the predominance of F. langsethiae and F. poae. Mycotoxin levels are also likely to be low, although extensive lodging and delays to the harvest due to the prolonged wet weather may raise toxin levels in some crops, particularly in the East and South West where there was a higher incidence of F. graminearum. This may explain current reports of the presence of pink grains in some grain lots, particularly in the Norfolk area. Grain is being rejected if more than 3-5 pink grains are present in a 1kg sample.

Table 1: National incidence of FEB


Year	% ears affected

10 year mean (1994-2003)	3.5
2000	4.9
2001	2.2
2002	3.1
2003	7.5
2004	3.0

Table 2: Species responsible for FEB symptoms 2000-2004


	% samples infected by FEB pathogens
Year	F. avenaceum	F. culmorum	F. graminearum	F. poae	F. nivale	F. langsethiae

2000	14	16	15	22	55	-
2001	6	13	7	61	0	26
2002	8	18	29	30	36	5
2003	24	11	35	39	32	1
2004	25	6	29	29	6	51

	RAPID ACCESS TO THE LATEST REGIONAL CROP PEST AND DISEASE LEVELS