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Plum Curculio Varietal preference

Posted by Mike Biltonen 
Plum Curculio Varietal preference
April 02, 2013 07:45PM
Does anyone have info or insights in to apple variety preferences of plum curculio? If any, of course.

Mike Biltonen, Know Your Roots
Zone 5b in New York
Re: Plum Curculio Varietal preference
April 20, 2013 03:25AM
I dont think that it has a preference altough it is attracted to more ripened fruits.

For example, my orchard has the dubious honor of being the fort one infested by Plum Curcilio, year after year (out of the 70 or so that are part of our agro-club).

The agronomist told me she does not bother looking for it in my Empire (that are closer to the wooded area) but goes straight to the Jersey Mac where the bug is found.
Re: Plum Curculio Varietal preference
May 16, 2014 09:13PM
In our orchard, PC clearly prefer Liberty and Prima over the other varieties we have, including Cortland, Freedom, red and golden Delicious, and Northern Spy. We used Primas exclusively as trap trees until we grafted them over to another variety, they were so buggy.

Bear Swamp Orchard
Zone 4b in Massachusetts
Re: Plum Curculio Varietal preference
May 31, 2015 04:59AM
I have just started following this. y ou say Plum Cucurlio goes for the ripest fruit but I thought it was an early season pest - right after petal fall. My earliest variety is Lodi (Yellow Transparent) and they certainly like it, so I guess the statement is true, though referring it to riper fruit when it is pea sized seems odd.

Anyway, someone told me their Plum Cucurlio management strategy was to shake them out of the trees onto a white sheet underneath. He said an amazing amount of the bugs drop out and it effectively controls the problem. Anyone else trying this?

I was suprised that none dropped out of my Mont Royal Plums about a week or so after petal fall. Is there a timing detail I am missing?

Colin Lundy
Colonial Inn Orchard
North Gower, Ontario
Zone 5a (Canada)
Zone 3b (USDA)
Re: Plum Curculio Varietal preference
May 31, 2015 04:26PM
Pea-size, marble-size, quarter-size ... curculio strikes just-sizing fruitlets, which as Colin rightly observes has nothing to do with ripening volatiles. Softer fruits might be a more relevant way of phrasing this, as summer apples will have that trait compared to keepers, but even so. This is more about other parameters we as humans cannot cue in on other than seeing where the beast itself goes. I have heard confirmation again and again about Liberty and especially Prima as preferences. Lush foliage also seems to be favored ala Chestnut Crab. And plums. The work of Tracey Leskey to define what those smells are could really help in creating effective traps for immigrating curculio.

What's most interesting are the dynamics of how to work this to our benefit. A few days ago I found one apple curculio on Summercrisp pear and two plum curculio on South Dakota plum. Surround went on the pears, plums, and pie cherries on Friday. No sign yet on any apple (including the infamous sawfly) but then king bloom fruitlets are at 8 mm at most at this point. The plumlets were interesting in that early scars show on the tiniest tip of the fruit as it came to be revealed after petal fall, being stung when pc itself was possibly even larger than the plumlet. The pace of different fruits flowering/ sizing can vary from spring to spring, plus any late pruning, can effect observed patterns ... but this is what typically takes place at my orchard in a normal year. Orchard layout with respect to curc overwintering sites is a big part of all this too.

Now we're into a few days of good rain. I will renew Surround on pear and prunus at that point, along with those apple varieties showing curc activity. Typically, this would be the application to include spinosad (Entrust formulation) for sawfly in the same spray tank, which is useful timing on the curculio front as purportedly there's as much as 50% crossover efficacy, especially when insects are irritated/ weakened by clay.

Those of you who have that "one tree" especially hard hit can take avail of a daily knockdown early morning onto tarps, or subsequently plan a targeted release of parasitic nematodes under the worse trees at the time of June Drop. So-called trap trees can be managed thusly, where now the draw factor is enhanced that much more by not applying the kaolin clay to these particular trees. A vinegar spray can make trap trees even more enhancing, perhaps by lowering BRIX, perhaps by correlating to whatever curculio thinks about in deciding where to go.

Lost Nation Orchard
Zone 4b in New Hampshire
Re: Plum Curculio Varietal preference
May 31, 2015 04:55PM
Interesting that this topic has come back up again. The timing of year is right, but it has been two years since I posted the original inquiry - maybe nobody has any problems with PC (lol).

That said, I am working with several growers that have a wide variety fruits that are susceptible to PC damage. Only one of these growers is 100% organic, the others have organic and/or other "lightly" managed blocks. As soon as this week (I want to wait until we're well through PC season), I plan on making an assessment of damage:

1. by variety
2. proximity to hibernacula
3. size/age of tree

Each of these elements plays a role in PC activity and to some degree or another, and I'm sure proximity to commercial orchards is also a key element in all of this.

I'd love to hear other people's experiences or thoughts on this thread.

Mike Biltonen, Know Your Roots
Zone 5b in New York
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