|Scab||See recommendations under 1/4-1/2 inch green spray. Do not extend intervals between sprays during a prolonged pre-bloom period.|
|Rusts and powdery mildew||See recommendations under tight
PINK THROUGH PETAL FALL STAGE IS A VERY CRITICAL PERIOD TO PROTECT AGAINST QUINCE RUST IN PROBLEM ORCHARDS. Under heavy quince rust pressure, control with the strobilurin fungicides, Sovran and Flint, may be inadeauate. For this reason we suggest including SI fungicides (Rally, Rubigan, Procure) during the pink to petal fall sprays. This may involve planned alternations of full sprays or selecting an SI fungicide soon after a quince rust infection period.
|Fire blight||Fire blight is most active during warm
weather. Blossom infection is aggravated by showers which
splash the blight bacteria. Apply streptomycin as needed
at 0.5 lb per 100 gal dilute or 1.5 lb per acre
concentrate. Streptomycin remains effective for 3 to 5
days. The effectiveness of streptomycin can be increased
by including the adjuvant Regulaid at the rate of 1 pint
per 100 gal tank mix, however, the increased uptake of
streptomycin with Regulaid is more likely to result in streptomycin
The plant growth regulator, Apogee (prohexadione-calcium), is registered for suppression of fire blight shoot blight. Shoot blight suppression results from hardening off of vegetative shoot growth starting about 10 days after the initial Apogee application, which should be made at late bloom when active shoot growth is 1-3 inches long. Recent studies at Winchester indicate that Apogee may be tank-mixed with Agri-Mycin and Regulaid, allowing Apogee to take effect while there is residual protection from streptomycin. Apogee is not to be considered a replacement for streptomycin sprays for blossom blight control. Registered rates for Apogee are 6-12 oz/ 100 gal dilute or 24-48 oz/acre. To reduce interference from naturally occurring calcium in the water used for spraying, ammonium sulfate should be added to the tank before Apogee, at the same rate per 100 gal of spray mix as for Apogee. Based on research at Winchester, the combination of 6 oz of Apogee plus 6 oz of ammonium sulfate per 100 gal is suggested for moderately vigorous trees. An adjuvant such as Regulaid should be included to increase systemic uptake of Apogee. Vigorous trees might be more responsive to the 12 oz Apogee rate than to the 6 oz rate. Shoot blight suppression is related to early hardening off of shoot tip growth within 10-14 days after bloom. Vigorous trees might benefit from further protection with additional Apogee applications in mid-season if shoot growth is resumed. Studies in WV showed that Apogee reduced shoot blight infections that occurred with hail injury in June. Do not apply more than 48 oz / A within a 21-day period. Practical usefulness of Apogee for shoot blight suppression in a given year might be estimated by the potential severity of fire blight based on the number of infection days that occurred during the bloom period, as well as tree vigor, varietal susceptibility, and disease history. Apogee treatment for shoot blight suppression would be most strongly suggested for vigorous young trees that have nearly filled their tree space. See pages 114-115 in the plant growth regulator section for additional comments about the use of Apogee for shoot growth and fire blight suppression.
1 See comments on fire blight under petal
fall and first
cover sprays pp. 39 and 42. Captan has been shown to
severely reduce pollen viability in hard-to-pollinate varieties
for 24-48 hours after application.
Effectiveness rating: E = excellent, G = good, F = fair
|Insects/Mites||Effectiveness||SuggestedChemicals||100 gal Dilute||Acre Concentrate|
|Defoliating caterpillars2||E = 4
3.5E, Nufos 4E or Yuma 4E
|2. Guthion 50W||8 oz||1.5 lb|
|Mites (ERM)||E = 5,6
||3. Imidan 70WSB||12-16 oz||2-3 lb|
|4. Bacillus thuringiensis||See label||See label|
|European apple sawfly (EAS)6||E = 2, 3, 8, 9, 10, 11
||5. 4Apollo 42SC||--||4-8 fl oz|
|Oriental fruit moth OFM)6|| E = 2, 3
or Onager 1EC
||See label||3-6 oz or 12-24 fl oz
|G = 8, 10, 11
|Dogwood borer (DB)
|| E = 1, 12
||7. Carzol 92SP
|G = 8
||8. 7Assail 30SG
|Mullein bug (MB)||E = 7, 8, 10
||9. Actara 25WG
|10. 8Calypso 4F
||1-2 fl oz
||4-8 fl oz
|11. Avaunt 30WDG||--||5-6 oz|
|12. 9Lorsban 75WG||10 oz
1 Most insecticides should not be applied during bloom. Install pheromone trap and inspect for male San Jose scale. Begin monitoring for gypsy moth.
2 If defoliating caterpillars become a problem, sprays of Bacillus thuringiensis are acceptable, affecting neither pollination nor fruit set. However, residual life is short.
3 Apply Asana against overwintered TBM larvae. Apply once to zone from trunk to drip line at a rate of 8.0 - 14.5 fl oz per acre. Use lower rate on small larvae (at pink) and/or on lower populations. Use higher rate on larger larvae (at petal fall) and/or on moderate to higher populations. Late application is preferred in order to protect Stethorus punctum overwintered in ground cover.
4 See note (7), 1/4-1/2 inch green spray (insects).
5 See note (8), 1/4-1/2 inch green spray (insects).
6 Apple at pink only if damage was
severe in preceding year. Otherwise treat at petal fall if
threshold is exceeded.
2.5-4.0 oz/A for MB; 5.5-8.0 oz/A for EAS, OFM, 8.0 oz/A for DB as
a drench to lower tree trunks.
Lower rate is effective for MB
When applied in a handgun spray (3 p or 2 lb/100 gal) to burrknots
will provide season-long control of DB.
|Virginia Apple Page||Virginia Pear Page||Virginia Peach Page||Virginia Fruit Homepage||Mid-Atlantic Regional Fruit Loop|
Alan R. Biggs and Douglas G. Pfeiffer