Agriculture Reference
In-Depth Information
(a)
(b)
(c)
Fig. 5.8.
The effects of undersowing leeks with subterranean clover on the numbers
on the leeks of adult thrips (a), thrips larvae (b) and the mean thrips damage
symptom class (c) of the leeks. Clover was sown in mid-April and the 22.5 m
2
leek
plots were planted in mid-June. Clover was mown when it exceeded 15 cm in
height. Leeks of symptom class 2 and above are of unacceptable quality for
European markets.
▫
, Monocropped leeks;
, undersown plots adjacent to
monocrop plots;
, undersown
60 m distant from monocrop plots (bars ± standard error) (from Theunissen and
Schelling, 1999. Courtesy of the
International Organisation for Biological Control
Bulletin
).
, undersown 30 m distant from monocrop plots;
●
