North American Fruit Explorers mailing list at ibiblio

[derry&bill <wchase@interchange.ubc.ca>]

Hélène,

It's not really a caterpillar, but a caterpillar-like pest. It is the larval 
form
of a sawfly. It looks like a caterpillar and it is green, smooth with black 
spots
and a black head. Hymenoptera Family. A British reference calls it Nematus
ribesii.

The sawfly lays eggs along the underside of the veins of the currant bush.
Depending on the weather, in south coastal B.C., the egg hatches at the end of
April. There may be a second generation in June. They pupate in the soil 
beneath
the currant bush. The sawfly emerges and flies up into the currant bush to lay
eggs.

You can diagnose it by the fact that the veins of the leaf remain, the damage 
is
noticed when the bush is half-eaten. When you look at the half-eaten leaves, 
the
caterpillars are all over the edges of the leaf chewing. There are far too 
many to
be squished.

I don't know if it's possible to put a weed cloth under the bush to interfere 
with
the pupating. Maybe the birds would eat the pupating caterpillars or maybe 
they
would die if they were not able to get into the soil.

The sawflies really liked my Jostaberry (until I deleted it a few years ago) 
and
sometimes eat my red currant, Jonkheer van Tets, but they never eat my black
currant, Black Reward.

The pesticide is Methoxychlor.

Derry

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Derry Walsh & Bill Chase
wchase@interchange.ubc.ca
Aldergrove,  B. C.,  Canada
phone/fax (604) 856-9316
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Home web page  http://www.interchange.ubc.ca/wchase/HTML
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: Hi Derry,
: Is this caterpillar green with some black markings? Is the adult a small
: pale white blueish butterfly (daytime butterfly) that visits the currant
: bushes late Spring?
: Hélène, zone 3a