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Healthy Fruit 2008 Vol. 16:15

Jul 15, 2008

Observations from Belchertown

I have not specifically hung apple maggot fly (AMF) traps this year, however, reports from elsewere suggest trap captures have been rather high. The moist soil conditions have certainly not hindered their emergence. Suffice it to say that now is the time to hang red balls and/or apply an insecticide -- best options include Guthion, Imidan, Surround (apply as often as needed), Assail, and Calypso. All are rated excellent against AMF, and should give two weeks of coverage. Early harvested apples are more susceptible now to AMF injury, but watch pre-harvest intervals as we move into late July and early August.

We finally had to treat for potato leafhopper (PLH) last week in young orchards. This year it seems like there have been real 'hot spots' of potato leafhopper, and where they are present, can cause significant damage to young apple trees. If you still have live PLH in young orchards it's still worth treating. Otherwise, we are probably over the hump on this one.

You should be applying calcium in all apple cover sprays (or more often). Calcium chloride is the most common source. See the excellent fact sheet F-119R Foliar Calcium Sprays for Apples for more information.

Finally, consider collecting leaves for leaf analysis towards the end of this month. You can do apples, peaches, and cherries. Ordering information and forms can be found in the Soil and Plant Nutrient Testing Laboratory section. I recommend sampling blocks every three years. Leaf analyses, along with soil samples, are the best way to tailor your fertilizer application(s) and avoid over-applying (fertilizer is getting very expensive) or under-applying, resulting in deficiency and reduced yields.

J. Clements

Japanese beetle making an appearance

Japanese beetles are ramping up and can get out of hand rather quickly. Their presence is more-or-less scattered, but where they are abundant, can nearly defoliate trees. They are particularly problematic on young trees, stone fruit, and they seem to really like Honeycrisp apples. Sevin or neo-nic insecticides -- Calypso, Assail, Provado are adequate control options. Surround also works, but works best when used with one of the neo-nics above.

J. Clements

Sooty blotch and flyspeck alert

We have clearly reached the threshold where fungicide treatment for the summer diseases sooty blotch and flyspeck is necessary. From here on out, the question becomes 'how long can I go between fungicide sprays?' Dan Cooley, in one of last year's Healthy Fruit, put together a table that tells how long your fungicide coverage will last depending on the funcide used and how much rain we get:

Table 1. Fungicides for management of sooty blotch and flyspeck. Protection is gone when either the days of protection or amount of rain necessary for wash off, whichever comes first, have been met. (Based on tests by D. Rosenberger)

Treatment (rate/100 gal.)
Days of protection
Rain (in.) to wash off
Tospin M 70 WP or WSP (3 to 5 oz.) + Captan 50 WP (1 lb)
21
2
Flint 50 WDG (0.67 to 0.8 oz)
21
2
Sovran 50 WG (1 to 1.6 oz)
21
2
Pristine (5 oz)
21
2
Captan 50 WP
14
2
Ziram 76 WP
14
2
Captan 50 WP (1 lb)
10
1.5
Ziram 76 WP (1 lb)
10
1.5