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Article 498 (28 more) in alt.sustainable.agriculture:
From: ssouther@ent1.ent.ncsu.edu (P. Sterling Southern)
Subject: tomato fruitworm follow-up
Originator: ssouther@ent1.ent.ncsu.edu
Organization: Dept. of Entomology - NCSU, Raleigh, NC
Date: Wed, 30 Dec 1992 14:15:08 GMT

In response to the recent postings on the tomato fruitworms in
Texas, a couple of minor corrections are offered (us technical types get
hung up on details you know).

The corn earworm, cotton bollworm and tomato fruitworm are indeed
all the same species - Helicoverpa zea.  The tobacco budworm is the
closely related Helicoverpa virescens.  Both H. zea and H. virescens can
occur on tomato and as the two species are hard to tell from one another
its a real question which one (or both) is the culprit here.  The local
extension service can probably get you an ID if its important to
you.

If H. zea is the problem, separating corn and tomatoes might be
somewhat helpful (H. virescens doesn't attack corn).  Be aware, however,
that the Helicoverpa moths can fly miles between egg-laying sessions and
that, depending on crop stage, the corn may actually act as a trap crop
being more attractive for oviposition than the tomatoes.  (Silking corn
is highly attractive.)

Bacillus thuringiensis is effective against either species.  It is
as was pointed out, sold as Dipel (also Javelin, Biobit, MVP and many
others).  It must be ingested to be effective, so putting it where
the larvae are is important.

Speaking of coverage, insecticidal soaps are relatively effective
against aphids or whiteflies.  Since their control is physical,
that is they must pretty well cover the insect to work, good coverage of
the plant using a fine misting spray will give best control.  I would
also say that they will work best when its hot and dry, but in Texas
that's not likely to be a problem.  Its always wise to check one plant for
possible phytotoxicity before treating the whole crop (or the other
plant, as the case might be) with a soap under similar weather
conditions.  (Very similar chemicals are used to regulate plant
growth by desiccating tender buds.)


DISCLAIMER:  The opinions and ideas expressed in this communication
are my own and should not be interpreted as representing those of my
employer.  In making these statements, I am acting personally and
not  in any official capacity.

-- 
| Sterling Southern, NCSU-Entomology, Box 7613, Raleigh NC 27695-7613   |
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