Resource Guide for Organic Insect and Disease ... - Cornell University

EUROPEAN CORN BORER (Ostrinia nubilalis)
The European corn borer has over 200 host plants and is primarily a pest of corn. Pepper and
eggplant are also relatively common hosts, and tomato and potato are less frequently affected.
In the spring, adults lay their eggs on plants, and the emerging larvae bore into stalks (Photo
7.6) or fruits. Larvae usually enter the fruit under the calyx or sometimes directly through the
side and feed inside. Secondary rotting of infested fruit is common.
Cultural Control:
1. Crop rotation is of only limited value because adults can easily fly between fields.
2. Some pepper varieties differ in their susceptibility, but there are no truly resistant
varieties.
3. The effectiveness of spray materials can be increased by using pheromone traps to
determine peak activity periods and treating accordingly. Check with county extension
for any available IPM forecasting services.
1. Release of Trichogamma wasps has been shown to be effective. Trichogramma
ostriniae is a tiny wasp that is smaller than a pinhead. The female wasp lays her eggs
inside the European corn borer eggs. Usually, all of the eggs in the mass are destroyed,
and the whole egg mass turns black. For details on using this beneficial insect, see:
http://nysipm.cornell.edu/factsheets/vegetables/swcorn/trich_ost.pdf.
Materials Approved for Organic Production:
1. Bt kurstaki: There have been no recent studies on peppers. Bt may be effective, though
it has a very short residual protection. Timing the spray to catch the borer during its
short time outside, before it bores into the pepper, is difficult.
2. Spinosad: Recent studies: three good, one poor result on this crop.
FLEA BEETLES (POTATO FLEA BEETLE – Epitrix cucumeris, TOBACCO FLEA BEETLE
- Epitrix hirtipennis, PALESTRIPED FLEA BEETLE - Systena blanda, and EGGPLANT
FLEA BEETLE - Epitrix fuscula)
Flea beetles (Photo 7.7) are common pests of potatoes, tomatoes, and eggplants when the
crops are young. Their feeding causes small holes in the leaves. Under light insect pressure and
good growing conditions, seedlings and transplants will grow out of the damage. Eggplant
is especially attractive to flea beetles, and small transplants may need protection. The species
that attack the Solanaceae are not the same as those that attack brassica crops or sweet corn,
which is important when considering crop rotation.
Cultural Control:
Row covers work well but can be expensive. Crops under row covers usually produce earlier
yields.
Materials Approved for Organic Production:
The studies below were conducted primarily on flea beetle pests of other crops, particularly
brassicas. Results may be different on flea beetle pests of solanaceous crops.
1. Rotenone is recommended in the older literature, BUT it is no longer a registered
insecticide and may not be used.
2. Spinosad: Research trials have indicated that spinosad can be moderately effective,
though results are variable (three fair and two poor results).
3. Neem products are similarly effective (two fair, two poor results). Please see the neem
material fact sheet for a discussion of the different types of neem products.
4. Pyrethrum: Pyganic has shown variable results (four fair, two poor) even with high
rates.
5. Kaolin clay (Surround): Recent trials have shown three poor results.
Note: Since flea beetles can re-colonize rapidly, especially on sunny days, frequent treatment
with any material may be required. Treatment of all susceptible plants in the field is advisable in
order to reduce influx from untreated areas.
58 Organic Resource Guide