PREHARVEST DROP CONTROL
Cultivars that do not hang well to the tree when mature can be treated with a growth regulator chemical to minimize drop. The material must be absorbed into the leaves to become effective. Therefore, it will not be effective if the foliage is seriously damaged by insects, mites, frost, etc. For best results, sprays should be applied dilute to completely wet the foliage. Concentrate application may produce uneven response within the tree, especially in large trees. However, application by aircraft will likely be better than no application at all if ground application of dilute spray is not possible. This material does not overcome drop that is caused by nutritional deficiencies. Do not mix pesticides with a growth regulator chemical.
NAA (naphthaleneacetic acid). This material should be applied when drop of a significant amount of many-seeded, blemish-free fruit commences. Delay application as long as possible in order to obtain maximum preharvest drop control. However, with late cultivars, the application should be made before frost injures the leaves. Once the foliage has dried after application of NAA, rain should not decrease the effectiveness of this material.
The restricted entry interval and preharvest interval for NAA products are:
24 hour REI and 2 day PHI for K-Salt Fruit Fix; 48 hour REI and 5 day PHI for Fruitone-N.
Table 25 - Use of Preharvest Drop Compounds
|
Cultivar |
Material and Rate* per 100 GALS. Dilute |
Remarks |
|
EARLY SEASON |
||
|
Quinte |
NAA, 10 ppm |
1.NAA generally causes direct ripening of fruit and the amount of ripening increases as the concentration and number of applications increases. 2.NAA will reduce rate of drop for 7 days. Longer drop control can be obtained by using of a repeat application after 7 days. 3. Federal regulations limit use of NAA to two 20 ppm applications. Fruits cannot be harvested within 2 days after application of K-Salt Fruit Fix; 5 days for Fruitone N.
|
|
Early McIntosh |
||
|
Puritan |
||
|
Milton |
||
|
MID- and LATE SEASON |
||
|
McIntosh |
NAA, 10-20 ppm |
1.See Notes 1, 2, and 3 above. 2.NAA used at single (10 ppm) or double (20 ppm) strength will reduce the rate of drop for about 7 to 12 days, respectively. Longer drop control may be obtained by using of a repeat application after 7 to 10 days. |
|
Macoun |
||
|
Baldwin |
||
|
Rome |
* Product labels specify number of ounces needed per 100 gallons to make 10 ppm of NAA.