SUMMARY (Today's Headlines): No more tipworm or fireworm generations, Outbreak of Red-headed Flea Beetle, and at least in central Maine very low fruitworm and fruit rot thus far.

Tipworm is past (finished) for the season, at least for central Maine.  No eggs, larvae, or pupae were found in 80+ new-growth tips from two tipworm-heavy central Maine sites with Early Black and Stevens varieties (buds for next year were already present in the Early Black).  I suspect the remainder of the state is free of any new tipworm as well and I'll be testing out that suspicion downeast tomorrow in Columbia Falls, Dennysville and Calais.  If that is not the case, I will post an update here. 

Blackheaded Fireworm is also past for this season.  The eggs for next year's brood have already been laid (undersides of leaves).  Even the moths are gone now, but I did find a single, late, larva at an organic site yesterday that had some severe pockets of them this season.  But any larvae at this point would be rare, and would only be stragglers, so spraying would not be helpful.  The damage for this season is already done.

***Another pest I've not seen before*** Twice now this season I have encountered a cranberry insect pest that I've never found in Maine cranberries before, and each time it has been at very high outbreak levels!  This time, it's a small black beetle called Red-headed Flea Beetle (blueberry growers will be familiar with this pest, but I've never seen it on cranberry in Maine before).  What's worse is that both of these new outbreaks have occurred at the same central Maine site! [The earlier case was blunt-nosed leafhopper]  And don't pay much attention to the "red" that's part of its name, by the way, because the red color on the back of its head is very subtle and just looks black except under proper/sufficient lighting [see photos below].  For those of you who happen to have the UMass book, Cranberry Insects of the Northeast, page 60 is the page to turn to for a good description of this pest.  They feed on the outer surface layers of leaves (moreso the undersides of the leaves), leaving only the veins underneath, while usually leaving the top leaf surface intact.  But they also gouge the berries, and overall, their feeding can significantly impact bud development for the following year when their populations are high like the situation I encountered yesterday (and this was not at an organic site).

Cranberry fruitworm and fruit rot levels in at least central Maine so far appear to be very low, even at an organic site that I visited yesterday.

Nutrition Reminder: From now through early September is the recommended period for doing tissue testing.
 

August 4 

Fungal concerns: Thus far, I have not found any leaf spots anywhere, except for one bed in Jonesboro with what appeared to me to be a somewhat mild case of Red Leaf Spot.  I am very doubtful that the Valdensinia leaf spot fungus affecting the wild blueberries (the one making news now) will be able to become established in our cranberry beds, especially in light of how aggressively the blueberry growers are managing for it (via burning) when they find it. [It is uncertain at this time whether or not the fungus is even capable of moving from blueberry into cranberry]

Blackheaded Fireworm (some variability with 2nd-generation): I visited two Washington County sites yesterday that each had a significant issue with fireworm.  At one of the locations (more inland than the other), the damage was far more extensive--large areas with brown/dead & skeletonized leaves--but there were no moths and no larvae to be found and the regrowth (new tips) looked very good to me.  At the other, closer-to-the-coast location, there were many fireworm larvae still to be found, from the same areas where 1st-generation larvae (i.e. their 'parents') had feasted about a month earlier.  The brown patches, however, were all but gone now, with new growth having come in, and most of the 2nd-generation larvae I found yesterday were fully mature and so I would not expect them to be doing much more damage before pupating.  Because there were so many larvae there, though (~30 in 50 sweeps or avg. of 15 per 25 sweeps), I was surprised to NOT see any brown patches!  Perhaps some browning will still take place, in a delayed fashion, but the grower also sprayed Lorsban last evening so hopefully now the fireworm will cease to be a concern at that location for the remainder of this season.  Even without a spray, it appeared to me that the population was mostly finished with its larval (feeding) stage.  Keep in mind that the literature now says that Blackheaded fireworm may sometimes squeak out a 3rd-generation, but I have yet to see evidence for that here in Maine and their timing this year appears to be the same as it has been each year since they first began to show up on a few of our commercial beds back in 2004.  This pest overwinters as an egg, which is why it would be difficult for a 3rd generation in Maine to make it from egg, to caterpillar, to moth, and then to an egg again, before it became too cold.

Blunt-nosed Leafhopper Update: No additional sites have turned up any of this bad guy.  It remains to be seen if the heavy infestation I did find has come under control yet or not.  Initially, the numbers held constant for at least a week, despite at least one application of Assail (but the weather during that period was still rainy).  I am hoping that when I check the site again tomorrow (following some better weather and some additional sprays that were planned) the sweepnet results will be vastly different.  The adult hoppers themselves have pretty good longevity, as they are able to survive until the first hard frost or not long before that time.  Most of the feeding that occurs, however, is done during the nymphal stages before they reach adulthood, and that period--which lasts about a month--should be ending soon. 

Cranberry Fruitworm: The sites I have been visiting have berries that are pea-sized and larger, so the cranberry fruitworm eggs should be on berries and on the verge of hatching (those along edges generally show up ahead of the remainder of the bed).  I have not seen any fruitworm-inhabited fruit as yet.  If you haven't sprayed yet -- due to poor weather no doubt -- do not delay any longer.  And remember, Assail is labeled for cranberry fruitworm.

Cranberry Tipworm: The sites I have visited most recently are sites where the tipworm wasn't targeted or managed very aggressively (rain was also an issue), so cumulative damage is very high at those sites (80 to 90%).  Current infestation levels, however, in terms of new eggs or larvae, are very low.  Most of what I am seeing in the field--and in my samples--is month-old injury or older.  But everyone's tipworm situation has been a bit unique this year, making it difficult to generalize.  One can find significant variability from one bed to another, for example, even at the same site, depending on pruning and/or sanding practices, differences in spray timings, etc.  For some growers, the fireworm has caused concern over tipworm to take a back seat, and anytime you have high fireworm levels, the tips in those areas will be totally consumed, meaning there are no tips left for tipworm to live and develop in.

July 19 

[NEW: Click HERE to tell me what you are seeing at your site, if anything]

I suspect that the serious infestation of Blunt-nosed Leafhopper I encountered on July 10th in central (central-southern) Maine was a very rare and isolated phenomenon, but I will be checking three additional sites tomorrow to see if I pick up any more in my net, and I will be updating this page with more information about it as the situation develops.  Assail has been used at the infested site (later that same day), so I am hoping that tomorrow my sweep net will be empty when I sweep the same location again.

Out-of-Bloom Counts: Other than the infestation of leafhoppers mentioned above, things appear to be pretty routine right now, with most growers probably reaching (or recently surpassing) the 50% out-of-bloom mark.  This is an important benchmark for timing one's cranberry fruitworm sprays.  [Visit the fruitworm page for more details about this, and for help with the formula for determining your out-of-bloom percentage.]

July 8

Spanworms began showing up at the end of June, and are still being found, but mostly below threshold, or--at their highest so far--right at the threshold of 4.5 per 25 sweeps. But if you haven't sprayed any insecticides this whole season, it would be a good idea to sweep now to check for spanworms (inchworms), even if your bed is in full bloom, just to be on the safe side.  Wait for a sunny and dry day, if there 'is' such a thing as of late, as that is when they would be most active on the uprights and would be feeding.

Blackheaded Fireworm: Some severe patches of BHF were found at one Washington County site (but only on a single bed at that multi-bed location).  No bed is safe, though, if even one of your beds has patches of fireworm present, as the moths that result will happily spread to any other bed for subsequent generations!  Currently, the Washington County population I found is in the adult/moth stage now, and I suspect sprays for Cranberry Fruitworm control will overlap nicely with the start of the 2nd generation of the blackheaded fireworm caterpillars.  And remember, Assail is labeled for blackheaded fireworm, and it also has the potential to help greatly with tipworm (as a bonus), depending, perhaps, on the application method (read the following tipworm section).

Cranberry Tipworm: Tipworm findings from the three most recent Washington County sites I have visited (July 2nd) are interesting. Two of the sites had high tipworm populations (current infestations of 55% and 70%) and one of those sites had high egg counts (30% of the tips with one or more eggs). The site with 55% had not used anything yet this season.  The latter site has used two applications of Assail already this season, but whereas it was by chemigation, it makes me even more suspicious that perhaps there are too many things that can go wrong with Assail's effectiveness (against tipworm) when applying it by chemigation, versus a boom sprayer -- boom sprayer sites have had only 5% and 10% tipworm infestation levels after only a single application of Assail.  But few caterpillars have been found at any of the Assail sites, regardless of application method, so the pests that are on the label for Assail appear to be controlled just fine (chemigation or otherwise). The third site I checked has had only a 3% tipworm infestation so far this season, with few insecticides of any kind (I think) used, as evidenced by several patches of very heavy blackheaded fireworm populations.  So why so little tipworm at that site?  The answer may rest in the fact that it also looked as though there may have been some frost damage at that location, so my educated guess is that the frost came late enough in the season that it dealt the tipworm a major blow.  I saw this to be the case at a site in Waldo County this season as well (verified by the grower).  But I'm not suggesting you allow your crop to be hit by frost as a means of controlling tipworm! 

Update on the site in Perry: I finally found a tip with tipworm--a cocoon--at that location from a sample of 40 tips that I took on June 26th, which tells everyone that there is tipworm at that location, but something in the environment (not any insecticide) is keeping the populations very low!  A few growers were with me, and we couldn't find any tips with cupping during the time we were actually there, but as I said, one did end up being in my random sample that I took.

False armyworm populations seem to be past now, except for any strays or stragglers that may have escaped and would thus only be feeding at night.
 

June 23

Cranberry Tipworm: Still zero tipworm at the location in Perry as of June 18th (an ongoing mystery).  I cannot find tipworm there, either in person, or in my samples.  An organic bed in that same region of Washington County showed a tipworm infestation of just 13% -- which is relatively low, but is certainly higher than the 'zero' situation in Perry, which is not organic but not far from it (only Bt is used for insecticides there).  An organic site in central/central-southern Maine registered a tipworm infestation of 15% as of June 5th.  I will visit that site again early this coming week for another measurement. 

For growers who have used our newest material (a neonicotinoid), results have been interesting, and by and large are very good thus far.  1st and 2nd-instar larvae are most susceptible to the material, but it occasionally kills 3rd-instar maggots as well (see photo showing a pair of dead 3rd instar larvae--they aren't as plump or 'moist-looking' as when they are alive, and of course, they don't move at all when they are dead (*LOL*) but you can't tell that from just the picture.).  A somewhat southern Maine grower that used the new neo. in mid-May had only a 10% level of tipworm early in June (and no fireworm, either).  I will check that site again early this coming week as well.  A boom sprayer was used for that application, and also for an application for a large grower in Washington County which has extremely low tipworm populations currently (samples from two beds of just 5% and 0% infestation levels--a truly remarkable turnaround from levels seen in previous years).  On the bed where my sample yielded 0% tipworm, however, I did manage to find some tips with tipworm while I was in the bed but I had to look very hard to find them, and only found four.  Apparently the population was so low, though, that my sample of 40 random tips turned up nothing.  That doesn't happen very often, to say the least.  Myself, and the affected growers as well, are wondering if perhaps late-season applications of the same material may have knocked down the populations so well last year that they have simply been very low to start out the 2009 season.  I think that is a strong possibility.  One Washington County grower told me that he in fact did get good tipworm control late in the season last year and is already seeing--he thinks--a much improved density of flowering uprights in his beds compared to previous years!  This same grower differs from the other two in application method (chemigation versus boom sprayer) and in a sample of tips that I checked just this week, it appears the neonicotinoid only provided about 33% control, which has us somewhat questioning the effectiveness of his particular chemigation delivery method - perhaps coverage is limiting, or perhaps too much of the material is being washed off in flushing out the lines afterwards, or both. 

Cranberry Weevil: A few of this pest showed up in western Maine early this season.  I will be going back there in early July to see if there is much of a 2nd generation or not.  Cranberry weevil is seldom found in non-organic situations, but a finding I made last week at an organic site reminded me of the challenges that organic growers face -- in just 25 sweeps my net was speckled all over with cranberry weevils...far too numerous even to count.  I estimate there were between 200 and 300 weevils present, easily.  It provided me with a good photo opportunity, and in this photo set (from June 18th) you can really see the red color very well!  By comparison, DO NOT worry about any grey weevils you find (grey weevils have been turning up lately, as they often do, but the grey ones are not of economic concern in cranberry).

Blackheaded Fireworm: Only seeing this pest in central and western Maine so far this season.  The populations in those areas are now emerging as the adult moths (see photo) and these moths will lay the eggs over the next week or two that will go on to become the 2nd generation of the season.  It is the second generation of larvae that can be so devastating to the plants, causing entire areas (from small to large) that will turn brown and appear to have been 'burned' by a fire.  The threshold for the larvae, when sweeping, is just 1 per 25 sweeps.  And also look for uprights that are webbed together and/or skeletonized leaves ("visual" method of scouting).

June 8

Callisto was used on one of the sites I visited Friday, with a great deal of bleaching already apparent and no visible damage to the cranberry vines.  Cinquefoil and dewberry were two weeds in particular that appeared to be in trouble from the Callisto application.  The weed giving a central Maine organic grower the most trouble currently is Reed Canary grass, which causes mechanical problems when attempting to dry-harvest (clogs up the picker).

June 1

So keep sweeping your beds, at least once per week, and inspect your sweep "catches" very closely.  A lot of the pests--as of June 1st--are so small at the start, that you have to let the net contents settle out, and brush them around frequently, in order to spot all of the caterpillars (in particular) that might be there.  It's important that you not miss too many of them, because the thresholds assume that you in fact do NOT miss any of them that you've gotten into your net!  And I can tell you that it's HARD not to miss at least one or two, which is one more reason why it's good to take multiple sweep sets if your counts are hovering close to any of the thresholds for anything.

May 22

I visited two central Maine sites yesterday--both with a long-standing history of tipworm (I'll be checking some downeast sites next week), and found quite a variety of things.  The Horsetails (equisetum) had sprung up at both locations, which is another signal for the start of tipworm.  [see photo of Horsetail plants taken yesterday] Oddly enough, though, I didn't notice any tipworm flies in my total--between the two sites--of 125 sweeps, so I also took some tip samples to see if they have started to lay eggs yet -- they haven't; zero eggs found as well, but I expect eggs to begin showing up very soon.  (NOTE: Only sample the tiny, new shoots that are down low in the canopy versus older tips that just have buds on them still--it's only on those brand new, tender shoots where you will find the first generation of tipworm eggs, with rare exception). Spring Caterpillars: False armyworms were out in force at the two central locations I visited yesterday, and at an ideal developmental stage (less than 1/2" long) for spraying.  They were close to the threshold at one site, and well over the threshold at the other site (avg. of 8 per 25 sweeps compared to the 4.5 threshold).  There were a few blossomworms at each site as well (which get added to your counts for false armyworms; basically, for this time of the season, just add together ANY caterpillars you find and use the 4.5 threshold value).  I also found a handful of other, newly-hatched caterpillars that were so small they could be almost anything.  My plan is to rear them out as long as I can, and at some point it should be easier to recognize what they are.  Some of the other miscellaneous insects I saw yesterday include just a few Flea Beetles (well below threshold), some non-pest weevils, and hundreds (if not thousands) of soil Collembola (photo) - those tiny, harmless, ubiquitous insects (also called Springtails) that resemble nothing more than little specks of dirt!

By request, here is a photo--which gets progressively more and more zoomed in-- showing a tipworm fly as seen in one of the yellow pan traps from last year. You may wish to save it to your computer somewhere, for future reference.  I'll also add it to our tipworm page.

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May 14