whitefly - 1
grown cucumbers in my greenhouse this year and whitefly have been
a real pest. I've tried various sprays, including neem and yellow
sticky traps, but don't seem to be able to get on top of them. Any
you've got a whitefly problem you need to spray at least three times,
at 5-7 day intervals, to kill successive generations as they mature.
The yellow traps do catch a few adults, but they don't give very
good control and have no effect on the young whitefly (nymphs),
which look like tiny scale insects and feed on the undersides of
You can use a systemic
spray such as Target, Confidor or Rogor 100 to knock down the adults
and affect the sap-sucking nymphs. Or try the less toxic Nature's
Way Insect Spray, but you'll need to make sure to get really good
coverage of both adults - which tend to fly around when you spray
them - and nymphs under the leaves. Be careful to follow label recommendations,
especially regarding withholding periods before eating sprayed cucumbers.
Whiteflies are common
on some garden weeds like sow thistle (puha) in warm parts of the
country, even during winter. So check around. That may be where
your problem is coming from.
Gardener, Issue 152, 2004, Page 26
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.