August 25th: I'm finding that the
cranberry fruitworm levels are high this year; that is to say, in the absence
of any control measures -- about double that of last year I would estimate.
So everyone who is following their normal control regiment for fruitworm
will likely see a bit more fruitworm injury come harvest time compared
to recent years, but hopefully those levels will still be negligible.
But for organic growers, losses could be on the higher-than-average end
of the spectrum I should think. Blackheaded Fireworm: There
are still some fireworm moths hanging out in the vines, probably laying
their eggs which will then overwinter. They are laid singly, on the
undersides of the leaves. But there won't be any more fireworm larvae
this season. Tipworm is well past being finished as well, and regrowth
in tipworm-infested areas looks very good to me, so perhaps those uprights
will still be able to produce flower buds before the plants go dormant.
August 12th: 2nd-generation blackheaded
fireworm moths began emerging from their cocoons yesterday (in central
Maine-but probably only a few days difference no matter where your location
is in Maine), so any damage you may find now that looks like fireworm is
most likely older damage and spraying would not be advised unless you are
still finding larvae in a large portion of the damaged tips that you check.
August 6th: 2nd-generation blackheaded
fireworm larvae can be found downeast, though they are mostly in their
final stage of maturity and many probably pupated already over the weekend.
But brown patches can be seen now from heavy infestations (if you have
any), so be looking for any brown strips or rough circles, especially near
bed edges. Look at any such areas closely for signs of larvae, webbing,
and/or leaf feeding. If you still are finding a larva in each
of the majority of the tips that you tease apart, my advice would be to
spot-treat those areas [with something that will kill them on contact],
if they represent a small portion of the bed. If there are lots of
spots, and you think they could be all through the bed (based on scouting
-- sweeping or visual method), you might need to treat it all, again,
using something that would kill them on contact because of how close they
are to pupating.
July 27th: As shared in my email,
cranberry fruitworm eggs can now be found on berries in Washington County,
so everyone else has them by now as well, and they have probably already
been hatching for a few days in central and southern Maine. It looks
to me like populations may be high this year, so anyone who typically sprays
for this pest should begin his or her control regiments now if you haven't
already. The standard practice is to then scout for the presence
of eggs to determine if a 2nd spray may be needed 10 days after the first
spray. Sometimes one spray is enough, if the timing is very good
and/or Intrepid--with a very long residual--was used. Scouting for
eggs with only a hand lens does not work very well (it never works for
me), so in the absence of any scouting, deciding whether or not to put
out a 2nd spray will boil down to your own unique economic situation and
degree of risk you may be willing to take.
July 8th: Be on the lookout for
2nd-generation fireworm larvae. I have been rained out a few times when
I was wanting to sweep at some downeast sites, but for those I've checked,
all has been quiet as far as insect pests go. But if you had any 1st-generation
fireworm at your location in June, or have had significant fireworm in
the past, then be on guard. To be safe from the worry of fireworm, any
given bed should be carefully checked every 2 to 3 days, looking for uprights
paired and webbed together at the tips (see photos--taken during a 1st-generation
infestation this season).
(click either photo for a larger view)
|
|
| Cranberry
uprights pulled together and damaged by blackheaded fireworm larvae (just
1 larva per picture). Photos taken June 22nd this year. |
June 25th: I revisited one of the
heavy fireworm sites (in central/south-central Maine) on Saturday, and
roughly 95% of the 1st-generation of larvae had apparently pupated. The
damaged tips were simply empty, except for the old webbing and frass. This
illustrates the importance of knowing what stage the target insects are
in when trying to make control decisions, especially for a bed that hasn't
been scouted very often. Just seeing damage is not enough to trigger a
spray. Of the fireworms I saved from central Maine to rear out, all of
them but one pupated over the last several days, and one of the earliest
pupae already hatched out, so the 2nd generation of larvae might be starting
somewhere in the neighborhood of July 4th across the heart of Maine.
June 20th: Two out of three sites
that I visted yesterday (downeast not included) had outbreaks occurring.
Blackheaded
fireworm was at 2 of the sites, and was at outbreak numbers at one
of the sites (way over threshold), and still at threshold at another site.
The other lone outbreak was one of cranberry weevil,
which is an equally serious threat. Weevil numbers were in the 8 to 10
per 25 sweeps range, and they were busy mating and laying eggs in the flower
pods. A weevil outbreak can wipe out an entire crop of flowers, so it is
always alarming when they turn up at all. I rarely see them, so this might
be an isolated case, but it's a reminder for everyone to stay vigilant.
I expect the fireworm and weevil did well because of the mild winter, and
so now we are having to contend with them. Fireworm is very high in
at least one area downeast as well.
p.s. Do not confuse the redder and more
robust-looking cranberry weevil with the smaller, grey-colored weevil that
is much more common on cranberry beds. The grey one is of no significance
to cranberries as it does not have the blossom-infesting/blossom-clipping
behavior that the cranberry weevil has. Also, cranberry weevils are most
active during the middle part of the day, especially when it's hot and
sunny. So scout/sweep for them then.
June 16th: Tipworm in central Maine
is starting its 2nd generation (fly stage), whereas tipworm in Washington
County is still in its 1st generation larval stages. I've not found any
threshold levels of insects anywhere yet this season, with the likely exception
of tipworm but there is no established threshold for tipworm.
June 6th: Nothing out of the ordinary
occurring. Found my first blossomworm of the season yesterday in Troy.
Today I am heading to Cherryfield Foods and hope to stop at 1 or 2 other
locations as well. Call me on my cell phone if you would like to be one
of those extra stops. The number is 356-9903.
June 1st: Finally found tipworm flies
in Troy today (could see them in my sweepnet after 50 sweeps), as well
as tipworm eggs and a few eggs that had already hatched out!! It
had been 7 days since I was there last, because of some rain interferences
earlier this week. And I captured at least one false armyworm in 50 sweeps,
plus
there was a blackheaded fireworm in one of the tips I sampled for tipworm.
I won't have an exact caterpillar count until after I take out my 'bug'
container from the freezer to look through it.
May 31st: Tipworm flies are present
now in the central Maine area. I also collected a sample of 30 tips to
check for eggs or larvae, in order to see how far along they might be.
I will have those results posted sometime over the next few days. Found
nothing else of note today.
May 27th & 29th: Be sure to
read the May 25th comments as well if you haven't already!
The flies that JH has been catching in
his cakepan trap are in fact tipworm flies, but his pots are on
black plastic so many of you--with colder situations--may not see them
for awhile still. No tipworm eggs or larvae found on the 30 tips
I collected from Troy on Friday. I did, however, to my surprise, find one
newly-hatched
blackheaded fireworm larva inside one of the tips,
burrowed down inside the elongating bud. The fact that 1 tip out
of 30 random tips contained a blackheaded fireworm larva is not
a good statistic. On the plus side, we now know the number of degree
days relative to the start of blackheaded fireworm larvae--as a bonus to
the tipworm work (once I calculate them out). (May 29th Update:
no tipworm or any other pests were found in the sweepnet contents from
Friday in Troy). Fireworm larvae usually don't get caught up in a sweepnet
very easily, and normally the first generation of this pest passes most
of us by unnoticed in Maine cranberry beds, so it hasn't always been
easy to know when the 1st generation was taking place (usually we don't
see them until the 2nd generation when their numbers are much higher).
Here's a few shots of the blackheaded fireworm
larva I found today. The shiny black head is one of the easiest characteristics
we have when it comes to trying to ID cranberry insects! If you see a shiny,
black head, you know it's blackheaded fireworm!
A blackheaded fireworm larva and the slightly damaged cabbage-head-stage
bud it was hiding in! |
Another photo of the same larva
(blackheaded fireworm).
|
May 25th:
Notice: Caterpillars have begun
in Troy! Caught at least 7 in 50 sweeps (or 3.5 per 25 sweeps, which is
below the threshold but more are on the way because these guys have just
hatched within the past day or two. They would probably be peaking on Monday,
at
the site in Troy. I would safely add 1 week, at a minimum, to that
time for Washington County growers, but you might start seeing the firstones
as early as this coming Friday (June 1st). Add 3 days to the date when
you find the first one(s), and that would be close to the peak hatching.
The ones I found today are all very small, and most of them--perhaps all
of
them--are false armyworms. I also captured a humped green fruitworm
larva (1st instar) on my own cranberry plot this afternoon.....first 'pest'
I've seen on mine this season. My plants are ahead of those in Troy
by at least a week I would say, because of their warm blanket of leaves
and fir needles that they had on them during the winter. I've not seen
tipworm on my own plot before (ever), so unfortunately I can't use my own
plot to help monitor for tipworm but I'm not terribly sad about that.
But speaking of tipworm: I would expect flies to be there (in Troy)
by now, but I won't be able to say one way or the other until tomorrow.
What I did was I emptied the contents of the 50 sweeps directly into a
large pretzel jug, then put the lid on it and stuck the whole jug in a
freezer when I got home. I did my sweeping late, when the flies would
be more active (around 7:30). It was also much cooler by then.
Tomorrow I can dump out what I caught and carefully sift through it, looking
at any small flies through my dissecting scope.
Idea/suggestion: I think this would
be a very simple way of looking for the first season's flush of tipworm
flies --> to simply sweep a lot (even a 100 sweeps would be
appropriate, per acre) when the time for tipworm seems like it should be
near (and when it is very dry so nothing will stick to your net),
and then empty the net's contents into a dry container that you can subsequently
place in a freezer. As early as a few hours later, you can dump everything
out onto a white surface, and use a brush or something to spread out the
mess and examine what you have with--at a minimum--a good magnifying glass.
I also collected 30 tips to look for eggs, in case the flies have snuck
past me. The buds still look tight, though, in Troy, without much
sign of elongation or lush, new growth, so it makes sense to me that the
tipworm wouldn't be there yet. It really 'truly' was a late Spring
this year, apparently.
May 22nd:
Troy: still only finding specimens
of the fly (not tipworm) seen in the photo below, to the right. Kathy Murray,
State IPM Specialist at our Dept of Ag, joined me in the search. We found
several of this 'other' fly, both in my sweepnet as well as in several
of the 8 soapy water traps I have set out. But the cranberry tipworm
should
be starting very soon. The plants there are definitely starting to green
up. I plan to go out again on Thursday.
May 14th:
Tipworm flies still not found in Troy
(nor any other cranberry insect pests), but this is the fly (below,
left) that I am looking for. This is a female (the females are orange
and the males are black). The orange color will be your easiest identification
sign, but you might also notice how much of a point the abdomen comes to,
seen in the photo just underneath the tip of her wings. The size of
this fly is very small (roughly half the size of one of those pesty
biting black flies).
female tipworm fly
|
A tipworm imposter!
With the naked eye, this midge was merely a tiny spec, barely visible.
I caught it today in my sweepnet and thought it might very well be a tipworm
fly, until I was able to see it under my dissecting scope later on. It
has some obvious dark stripes (like war paint) there behind its head. But
this is a good example of how easy it is to be fooled when you're trying
to find the very first tipworm of the season! |
May 7th:
Still too early for tipworm flies in Troy
(no flies found today, either in traps or by sweeping). Vines are still
purple. Also, still catching a couple of tiny flies very similar to tipworm
in terms of size - can be hard to distinguish from tipworm in the absence
of tipworm. Once tipworm flies are present, it is easier to tell them apart
from the other flies. I am starting to become a bit concerned about the
ease of any grower identifying tipworm flies with a trapping system--or
at least the ease of identifying the first hatching of the flies
at the start of the season (a dead tipworm fly with sticky adhesive on
it, or one that is soaking wet and has drowned in water, is a lot harder
to identify than a living specimen because you lose the behavioral 'clues'....the
very clumsy manner in which they fly around, for example....often ending
up on their backs in your sweepnet or box, and vibrating their wings while
still basically remaining in place or just spinning around).
May 2nd:
Looked for tipworm flies at the monitoring
site in Troy today (Howes bed - vines still purple). No tipworm found.
Will check again tomorrow and/or Friday. A close lookalike midge
was out, though, so be warned if you are trying to monitor on your own
that there are other tiny flies that can look a lot like the tipworm fly.
None of the imposters are orange, however, like female tipworm flies are. |
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