Our first webinar! We look forward to finishing it out next week.
Today, John started with updates about the current Codling moth and Apple scab situations in the area. He then began his webinar discussion of resistance management and beneficials, aided by some of his great photos from the field.
Please download the video recording below. We’ve also made the slides available in PDF form.
- Download the video recording of the May 8 webinarÂ here. Note: This is an audio/video recording.
- Download a PDF of the slides Â here.
Caller Dennis Norton recommended a couple of programs for iPad users who want to be able to join future webinars in real-time. The iPad currently doesn’t have built-in support of Flash video, which the webinar requires. Here are some options:
Call Transcript, May 8, 2012
(NOTE: We’re providing a transcript for John’s updates on Codling moth and Apple scab. The rest of the presentation was based on slides and photos, and will not be transcribed. Please download and watch the recording (above) to view that part of the presentation.)
John: Just about everybody had a few Codling moth fly last week on those warm nights around May 2 and May 3. In a lot of cases, the flights werenâ€™t in big numbers, and the numbers have dropped off even more since then because of the cooler nights.
The highest catch Iâ€™ve seen: in one orchard â€“ a fairly small, spread-out orchard with five traps â€“ four of the traps had between 1 and 3 CM, and the fifth trap had 42. That was in two nights.
So, we could assume that the biofix for CM was set on May 2 or 3, if you indeed caught some on those days.
However, one caveat: You need to take the following into account when setting your biofix. The viability/fecundity of CM eggs drops off dramatically for every day that the CM female is not able to oviposit after mating. Within 5 or 6 days, the entire egg mass would be worthless. So, even if you caught 6 or 7 or 8 on May 2 or May 3, if youâ€™ve had cold or windy nights in the 5-6 days since then â€“ in other words, conditions in which CM were not able to fly â€“ then youâ€™d probably want to disregard May 2/3 as a biofix.
On spraying a light-crop orchard
John: Â I want to use this webinar as a method to show a few photos of beneficials/biocontrols and to discuss means of putting together resistance management questions with ways to deal with a light crop. Basically, what can we do to reduce sprays and reduce resistance development?
Itâ€™s a straightforward procedure that weâ€™ve talked about numerous times, but have not had the opportunity to intensively apply it: That is, using insecticides only for controlling the direct fruit pests (Plum curculio, Codling moth, and Apple maggot), and being very management-intensive even with those sprays.
What does that mean? In many orchards, Iâ€™d envision that they may not ever even put an entire insecticide cover on the whole orchard to control those three main pests. The way itâ€™s looking right now suggests that if you have a light crop but you still want to protect it, then managing sprays to maximize beneficials is a method that is custom-made for us this year. There is a staggering number of beneficials out there this year. Beneficials, predators, and parasites that in a normal year might take half a season to develop are already out there in huge numbers, doing work.
Grower: Do thresholds change with the alternative spray strategy youâ€™re suggesting?
John: It depends on the insect. What are your options for managing pests under a reduced crop? [PLEASE SEE WEBINAR FOR DISCUSSION ABOUT THIS QUESTION â€“ AROUND 00:15:00 TIME MARK]
On Apple scab
John: There are a lot of other diseases that people might be concerned about. Black rot and White rots are two of them. Fire blight certainly was a big one last week. I know that some people had some severe weather (hail) in some places. Itâ€™s a horrible time of year. Not only did people have a damaged crop, but then you have a hail come through. Anyway, under those circumstances, I donâ€™t know if there could have been a worse time to have hail than during that warm weather. That got the bacteria going during a period of rapid shoot growth. CombineÂ rapid growth, warm weather, and Fire blight inoculum with hail, and you have a dangerous situation
But, as far as scab goes:
As long as youâ€™re not really close to the lake or up north, you should be done with primary. That is, the degree day model says that weâ€™re done, that the ascospores have developed. And most people have had a rain event since we hit that 99% maturity. From the modelâ€™s standpoint, all the ascospores should be shot out.
There seems to be a pretty clear demarcation among orchards. Some orchards have very visible scab thatâ€™s easy to find. Other orchards, for certain reasons, are completely clean.
I wanted to make a point about scab and cutting back on your fungicides: if you are clean of scab right now and want to reduce or eliminate fungicide use for the season, it would be unwise to stop fungicide treatments until you know for sure that none of the ascospores released during the rain event got through your cover. You have to wait long enough to see if those lesions will appear before you can let down the cover. In this kind of weather, it could take you 10-12 days before you might actually see a lesion on the tree. So, what does that mean? Probably one additional application of a protectant, probably at a half rate â€“ for growers trying to reduce their fungicide bill. Once you know that your scab is okay, then let the rest go.
[WEBINAR BEGINS HERE, 00:15:00 TIME MARK â€“ DOWNLOAD VIDEO]