Wednesday, June 8, 2011

Most Asked Questions of the Week

Here are some of the answers to the most asked questions this week. 

Thanks to the Utah Pests website for being such a great, reliable source for helping 

us diagnose the pest problems that we see on a regular basis.  They have wonderful 

pictures and up-to-date information for the homeowner.

This past week we have a lot people asking about what is wrong with their peach trees.  

They have lost lower limbs of their trees, the leaves came out in the early spring but now

have fallen off, or the leaves are misshapen. 

USU Tree Fruit IPM Pest Advisories provide nearly weekly updates on current insect

and disease occurences, biology, and treatment recommendations for Utah.  Updates run 

from mid-March through September. You can subscribe to their IPM advisory and receive 

updates by email.  


Coryneum Blight (Shot hole)

Shot hole lesions are starting to appear on leaves at this time. Shot hole (or
coryneum blight)
overwinters in buds and spreads from there to leaves and later in the season, to
developing fruit.
On the leaves, you will see small round holes that may be purplish or tan in color.
The center of the lesion will sometimes still be attached. Cool, wet weather
contributes to spread.
At the shuck-split stage, you can use Bravo (chlorothalonil, Daconil for residential
use), Abound,
Captan, Ziram, or Pristine.
And keep in mind that the most important treatment is an application of copper at
50% leaf drop in the fall.

Peach Leaf Curl

In the past, we have seen peach leaf curl in Box Elder, Davis, and Weber counties.
Peach leaf curl is a fungal-caused disease that affects peach and nectarine. We may see it
again this year due to the prolonged periods of cool, wet weather we have had this spring.
Damage may not be evident until later in May or early June. Infection occurs just as the leaves
are opening, and causes puckering and distortion of the leaves. The affected area is pink at first,
and then turns green, then brown. Leaves will drop. After the initial infections, new ones only
occur when temperatures are below 79 F.
If you see these infections, note that there are no fungicides that can be applied at this time.
The best treatment is a single application of a fixed copper applied at leaf fall.
For now, maintain tree vigor of infested trees by thinning more fruit than normal, reducing
drought stress with irrigation, and applying extra nitrogen fertilizer.

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