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

Other: There is one study showing fair control of potato leafhopper. Results have generally
been poor against whiteflies, pepper maggots, and psyllids.
Azadirachtin-based neem products showed good results against beet armyworm and aphids
(less so vs. green peach aphid). Less reliable results were obtained against squash bug,
diamondback moth, Colorado potato beetle, flea beetle, and Southern armyworm. No neem
products were effective against pepper maggot, squash vine borer, thrips, or whiteflies (Figure
1). Products tested include Align, Amvac Aza, AZA-Direct, Azatin, Azatin XL, Fortune Aza,
NeemAzal T/S, Neemix .25, and Neemix 4.5.
FRUIT CROPS
On fruit crops (Fig. 2), neem products have shown good results against: aphids, including
rosy apple aphid and wooly apple aphid; tarnished plant bug; leafhoppers, including eastern
grape leafhopper and rose leafhopper; and spotted tentiform leafminer. Results have been
mixed against white apple leafhopper, the apple lepidopteran complex, and mites, while those
against beetles, flies, blueberry caterpillars, psyllids, and scale have been poor.
6
Azadirach6n-­‐Based Products Efficacy:
Insect Pests of Fruit Crops
Good Fair Poor
5
Number of Trials
4
3
2
1
0
Aphids
Apple leps
Beetles
Blueberry leps
True bugs
(Hemiptera)
Flies
Grape berry moth
Pest
Leafminers
LeaDoppers
Mites
Psyllids
Putnam scale
Figure 2. Efficacy of azadirachtin-based products against insect pests of fruit crops.
140 Organic Resource Guide
GREENHOUSE APPLICATIONS
Neem has good potential for greenhouse use. Although relatively few research trials have been
conducted, some reports indicate good to excellent results against leafminers, mealybugs,
aphids, mites, flies, fungus gnats larvae, and whiteflies (Fig. 3). Often these results have
been obtained with only one application. There is generally a three to seven day delay after
application until maximum effect. As with most pesticides, efficacy will be improved with
better spray coverage. Results have been variable according to the plant species treated, but
good results have been obtained on chrysanthemum, coleus, marigold, pansy, wandering Jew,
German ivy, and poinsettia. Poor control with neem in greenhouses has been noted against
mealybugs on jade plant and black vine weevils on strawberries. Performance has been mixed
against psyllids on tomatoes.
More research is needed in this area, but there is clearly good potential for successful use of
neem products against commercial greenhouse pests.