North American Fruit Explorers mailing list at ibiblio

[Alan Haigh <alandhaigh@gmail.com>]

Now that Dennis has covered plum curculio from a research perspective I think it might be helpful if I submitted my own anecdotal experience with the beast in southeastern New York and nearby vicinities (zone 5 to 6).

 

I don’t pay any attention to degree days, I don’t know how absolutely reliable these models are, but in my neck of the woods there seems to be at least a week and maybe more range between when PC may appear in context of the phenological state of the apple trees.  Sometimes they appear almost right at petal fall of latest flowering apples and sometimes up to 9 days later.

 

Because I have to cover so much ground, even though I subcontract half of the spraying of my accounts, it takes me a week to cover all the orchards I manage in cooperative weather.  There is little range from site to site in terms of the actual point of petal fall of last flowering apples.  Fortunately Imidan allows some flexibility as I’ve often sprayed trees with PC already dancing on the applets but suffered little meaningful damage- at least for non-commercial production.

 

I almost always get good control on the sites I manage with 2 sprays of Imidan per site- the first within about 5 days of petal fall of latest flowering apples the 2^nd 10 to 14 days later.  In my region we only experience a single generation of this monster so this is adequate and also pretty much takes care of the other most destructive insects like Coddling moth.

 

In my limited experience with Surround, I never spray before petal fall because I’ve never seen a single PC on a tree before this time.  I apply Surround at petal fall and once a week for a total of 4 applications, making sure the fruit is thoroughly coated.  On about 4 sites this has worked well the last 3 seasons. 

 

I would recommend all home orchardists to use equal parts research and your own observation to determine your spray schedule.  I believe you will often find it advantageous to defer to the information your orchard provides over that provided by your states landgrant university.