Apple maggot fly absent some years?

What was the experience of apple growers this year who control or monitor apple maggot fly (Rhagoletis pomonella) presence around July and august? I'm in northeast Iowa and this is what I saw:

I hung red sticky balls on every apple tree on the perimeter of my orchard last year as organic control, but caught a total of 2 out of more than 100 traps. I hung these early enough to catch any flies entering from the perimeter. I observed no damage from maggots on my fruit, so I think they simply weren't here last year-- I'm thinking because of the very cold, long winter.

What is the experience of others, or has anyone read about this in the literature?

Darin Enderton
Owner/manager
Apples on the Avenue Orchard
Zone 5a (technically)



Edited 1 time(s). Last edit at 03/06/2015 01:01PM by Michael Phillips.

Ironically, here in New Hampshire, we saw the greatest levels of AMF damage ever. The two factors involved here were a small crop (thus far fewer fruit to "spread out" the damage) and hot September days making for continued oviposition on late varieties. Red sticky traps worked well early on but eventually a sizing crop lessens the effectiveness of visual traps. Honeycrisp in particular took a hit as the flies kept stinging away right up till harvest.

Winter cold was normal here (like what you experienced in Iowa) but we had good snow cover. AMF built up two years back when we also had a small crop due to the big blossom freeze that early spring ... and I wasn't as diligent about picking up the drops where trees had only a few fruit. I need to be proactive this year and do more with fruit fly bait with spinosad (GF-120) in addition to dozens and dozens of traps. Also keep in mind that yellow sticky cards baited with ammonium (to mimic bird poop) draw sexually-immature flies in the front part of the season.

Maggot fly species have other traits that can contribute to weird year cycling. Long dry spells delay emergence of flies from the soil, and in such years the early varieties may not take much of a hit. Then again, those ragtag larvae from late varieties have the ability to pupate for two years thus ensuring an AMF comeback after what seems a low-pressure year.

Lost Nation Orchard
Zone 4b in New Hampshire

Holy cow, up here in Northern VT got a massive crop of AMF, most I've ever had to deal with. Put up tons of red sticky traps, catching lots, but still getting some damage on early vars. Hoping if I can keep fresh traps up all season I'll minimize damage to mid season & later varieties. Last few years we've done a good job picking up our drops, so these guys are coming in from outside the orchard..thinking that last years massive crop loading in most wild trees around here = very successful year for AMF reproduction last year...& here come their offspring! Not willing to spray surround, too much hassle at harvest as I don't have a washing set up. Would spray Entrust if I had to, but would rather not, don't like the stuff...plus it's only effective for a week. But if this is peak AMF emergence, maybe one spray would knock back most of 'em?


Cate Hill Orchard
all standard trees, Zone 4a (colder some years)
Northern VT



Edited 3 time(s). Last edit at 08/24/2016 07:47PM by Josh Karp.

I included Entrust (spinosad) in my August 9 application to all trees in my main block showing fruit. That was intended as a 10-day wallop on AMF numbers as they were appearing pretty thick two weeks ago here. Now I see numbers building again and plan to do a backpack application today or tomorrow to preferred midseason varieties as the summer apples are now mostly picked. Fruit set here is light which makes the problem worse, as there's less apples to go around. Your description of a flood of wild immigrants from outside the orchard is spot on, Josh. It's like a pulse you can almost anticipate, given the huge crop last year and the very warm fall where the action continued -- bringing into play more eggs, more larvae, more trouble.

Lost Nation Orchard
Zone 4b in New Hampshire