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General Preemergence Herbicides. Now is the time to be applying Devrinol, Casoron, and Evital for preemergence weed control. Water Casoron in well after application; you want the herbicide in the top soil layers. Casoron volatizes easily so avoid applying when air temperatures exceed 60 F. Soil temperatures should be warm (50 F) so that you will get the boundary layer formed to get the best weed control (you want volatilization in the soil!). It is always best to NOT apply PRE herbicides just before a string of frost events, if possible. However, applying before a single frost event should be no problem. Devrinol should be watered in, too; you want the herbicide off the foliage and into the soil.
Frost. The tolerance for EB and Howes is 18 F; ST and BL are considered to be at 20 F. The new hybrid varieties seem to be closer to Ben Lear and Stevens, so growers with those varieties should gauge their protection needs on those varieties. The CCCGA’s frost service will be activated as of April 14 for all eligible members.
Winter Moth. We have a fact sheet for winter moth available. It has color photographs to aid in ID and management. Eggs begin hatching in mid-April. Larvae are usually seen mid-late April. The newly emerged larvae look like black-headed fireworm larvae; it is very hard to tell them apart at this stage. Young larvae can be quite voracious and do a lot of damage. The current thought is that if you find an average of 10 or more, you should consider treating. Once winter moth caterpillars become free-feeders, they are easier to control but have likely done most of their damage by that point. Be prepared to sweep early than usual (early May) and sweep more often, especially if you have had injury in the past. Intrepid and Delegate are probably the best choices; Orthene and Avaunt are good choices; Sevin and Diazinon are NOT good choices as spanworms are often resistant to these compounds. Here is a link to the UMass Landscape’s fact sheet on winter moth: http://www.umassgreeninfo.org/fact_sheets/defoliators/wm_id_man.html.
QuinStar. EPA granted our emergency exemption request for the use of QuinStar for dodder control for 2011. You can use up to 12.5 fl. oz/A per application of the 4L, not to exceed 16 fl. oz/A per season with a maximum of two applications. You can apply up to 8 oz/A per application of the Dry Flowable formulation, not to exceed 10 oz/A per season with a maximum of two applications. Irrespective of which formulation you use, you cannot exceed a total of 0.50 lb active ingredient/acre per season. Handlers have varying policies on the use of QuinStar for 2011. All growers should verify that their handlers will accept fruit treated with quinclorac PRIOR to using the herbicide.
Applications made earlier in the season (pre to early postemergence of dodder seedlings) seem to be most effective. For this year, I would guess application would go out May 10-15. Scout for early emerging seedlings on your bogs and time your application based on the appearance of seedlings. Applications made once dodder has securely attached to its host are much less effective. It is better to be EARLIER with QuinStar, rather than TOO LATE. A 30-day interval must elapse between applications and QuinStar has a 60-day PHI. If you have any questions about using QuinStar, please call me at ext. 21 and/or contact your handler.
We have had a report of dodder seedling emergence from Carver, MA. This does seem a bit early, but you should be checking to see what is going on on your bog. No need to panic at this point; there is time to apply QuinStar. The weather is predicted to be unstable for the next few days. In any case, you would want to see multiple seedlings emerging before spraying. Dodder usually takes about 2-3 weeks from early emergence to when most of the population is emerging. So, if you saw multiple seedlings today, you would still be in a good window to apply in 2 weeks’ time. Please see the recently released newsletter for more info on QuinStar.
The Entomology lab reports emergence of winter moth larvae. Winter moth has hatched and can be seen feeding on blueberry. Winter moth has been reported on cranberry this week at very low levels. It would be wise to sweep bogs to check as soon as good weather prevails. It is likely too early to be spraying for anything except winter moth at this point. Please see our fact sheet and photos below. Orthene, Avaunt, Intrepid, and Delegate are good choices for control; Sevin and Diazinon are NOT as spanworms are often resistant to these compounds.
We are posting photos of buds that Carolyn has looked at for gauging frost tolerance on our web site’s home page. We anticipate that new photos will be posted every 5 days or so.
The message has not changed much since last week. We have heard of a couple of growers that are opting to spray for winter moth. Frost nights and windy conditions continue to postpone preemergence herbicide applications. The latest pictures of frost tolerance are available on our home page. We have not yet had dodder emerge in the buckets that we monitor by the greenhouse on State Bog, however, a few reports have come in from growers. You should be checking YOUR bog in warm areas and trash removal areas for seedlings.
The Entomology lab recommends getting out soon to sweep your bog. When you have inspected your net, if you are not sure which insect you have, you can drop off samples to the Entomology Lab. Please bring unknown weed and disease samples to us to correctly ID. Ck the Chart Book as (esp with disease samples), there is a specific collection procedure.
The latest pictures for frost tolerance are available on our home page (from May 5). Winter moth larvae are out. The Ent Lab suggests not spraying until you have at least an average of 10 larvae per set and since they are spanworms, perhaps consider using 18 as your AT. We have heard of one report of 40-50 larvae in a sweep, so they are out there! Black-headed fireworm larvae are out as well, though not many. We have heard that there are a few cranberry weevil being swept, but again not many. It is definitely too early to spray for weevil at this point. False armyworm has hatched. Remember they eat a lot more than winter moth larvae and the AT is 4.5. QuinStar applications are going out now and now is the good window for many bogs. Next week should be a good window, weather permitting.
We are looking for a couple of sites to test QuinStar for dodder control. The study areas are pretty small and you would just need to block heads where our plots are whenever herbicides would be applied. This study would be easiest for bogs contracted under independent handlers since QuinStar use is not restricted and all fruit could be delivered. We would need to set the plots up ASAP. If you have a piece that you would be willing to let us use, call Hilary at ext 21 or Krystal at ext 13.
Dodder is definitely up and we are all hoping for a good spray window for QuinStar applications. Dodder ranges from newly emerged to limited coiling around their first host. QuinStar should still do a good job, even if coiling has just started. Next week is forecasted to be unsettled as well, so when the window opens, go for it. As I mentioned in the newsletter, it is fine to mix QuinStar and Callisto; however, we do not have any information on tank mixing with Delegate. If you have tried it or have information on doing that, please let me know (ext 21). Insect info is pretty much the same as last week. Winter moth larvae are out and getting bigger. The Ent Lab suggests not spraying until you have at least an average of 10 larvae per set and since they are spanworms, perhaps consider using 18 as your AT. Black-headed fireworm larvae are out and growers are trying to get sprays out to control them. False armyworm has hatched. Remember they eat a lot more than winter moth larvae and the AT is 4.5. Not much word on gypsy moth or blossomworm larvae.
The constant rain of the past week forced several growers to use short-term floods for BHF and/or dodder control. It was actually a good scenario as temperatures were cool and the window to spray was small or nonexistent.
If the weather holds, next week should be popping bug-wise. Be sure to get out and sweep. We anticipate that cranberry weevils should be out; possibly also BHF. Use Avaunt for spring populations of weevil. Winter moth larvae in the trees are getting quite large and if you find big larvae, sprays are probably not of much use at that point. However, if you continue to pick up small larvae, you could benefit from spraying. Spag may be slow to come along; we have not heard of much blossomworm, gypsy moth or false armyworm activity.
It is still a good time to apply QuinStar for dodder control. Callisto applications can be made for other weed control as needed. If you are chemigating either of these compounds, use 2-4 pt/A NIS or COC. If you are applying Callisto by backpack or broadcast applicator, use 0.25% v:v. So, in 1 gal of water, you would add 1/3 oz of NIS or COC. Spot-treating with QuinStar, use 2 pt/A (or 2 pt in 30-40 gallons water).
If you need to spray for upright dieback, do it ASAP. These must be applied pre-bloom. Fungicide applications for Phytophthora control must also be made pre-bloom. Contact Frank at ext 18 if you have any questions.
The weather has not been cooperating as far as getting sprays out. Wednesday was one of the best days so far and folks were out sweeping. Reports are variable, but high counts of weevil and BHF are in. Avaunt sprays have been going out for weevil. Winter moth is mostly through its cycle on the bog. If you are going to be using pheromone traps to time Spag, girdler or BHF infestations, traps should be out by June 1. How you use the trap count information will depend on your management choice. If using growth regulators vs BHF, timing is 2 weeks after ONSET of moth flight and another 10 days later; for other insecticides, applications are made 10 days after peak. For Spag, timing is 3 weeks after ONSET of moth flight (+ at least one more spray); for other insecticides, applications are made 10-14 days after peak.
There has been some confusion about what rates to use for QuinStar. The high-end rates (12.5 oz for the 4L and 8 oz for the DF) are leftovers from the first year we got the Section 18 permit. We had failures (related to the timing of application, but we didn’t know that at the time), so we asked EPA to increase the usual label rate. That’s the history. Here’s the now. The bottom line is that you should get good control with 8 oz of the 4L or 5.3 oz of the DF. It is probably best to get used to these rates as when the full label come through, this is what will be permitted.
Growth stages are really variable. Some bogs have barely 0.25 inch new growth and other are approaching jewel stage. Dodder growth seems to have been held back some due to the cold, wet weather. However, it should start to perk up when we get some nice weather.
We have had several reports this week of Spag in numbers above the action threshold (>1 per set). Some growers have discussed waiting until sprays are needed for cranberry fruitworm to treat for Spag (to try to save money and sprays). The Ent Lab discourages this consideration. They recommend trying to target the first generation (which is now). Although the larvae are getting large, Intrepid (growth regulator) can be a good choice for efficient chemigation systems. Confirm, a similar type product, can be used in Zone 2 areas. Chances are good that the timing for cranberry fruitworm and Spag will NOT overlap. If you do not treat the 1st Spag generation, you will have to chase the 2nd generation with additional sprays later anyway, so you really will not be saving any sprays (by not spraying now). Call the Ent Lab if you have additional questions. The Ent Lab also reports that Orthene seemed to do well against some of the early season caterpillars. Be sure to ck with your handler for application restrictions as different handlers are limiting the use of certain compounds and have dates past which certain chemicals cannot be applied.
First fungicides for fruit rot go out at early bloom, which may occur next week in some areas. Vine growth is very variable. Some bogs could see first open blooms in the next few days and some are still at roughneck.
If you are applying a second application of QuinStar, be sure to wait at least 30 days between applications. Callisto has a 14-day interval between applications.
Spag finds continue to be the hot insect topic this week. Some second generation weevils have been picked up. Now is also the time that you might be seeing true brown spanworms showing up as thread-like larvae on the rim of the net.
First fungicides for fruit rot go out at early bloom, which may occur next week in some areas. Vine growth is very variable. Some bogs could see first open blooms in the next few days and many are at hook.
Just after the frost events of last weekend, we have gotten reports of some cupping of the tops of uprights on bogs that were treated with QuinStar. Below is a photo of the injury. The vines seem to be coming out of it. We are not sure what is going on exactly but suspect that perhaps the herbicide is making the vines a bit more susceptible to cold injury. If you have seen this, please let me know. We will keep you posted on how the vines recover and respond.
The next message will be updated by June 21.
IPM Message June 24, 2011
Brown spanworm larvae may start to show up soon. Look for thin, thread-like larvae on the rim of the sweep net. Check pheromone traps weekly and change lures about every 3-4 weeks as needed. Several of our new products like Delegate, SpinTor, Belay, and Entrust are highly toxic to bees, so spray these products when bees are not actively foraging. Toxicity does drop once the spray dries. Cranberry fruitworm management is based on % out-of-bloom and some varieties have pea-sized fruit out there already. Try to get 2 estimates BEFORE 50% oob (rather than just 1); it makes your estimate more accurate. See page 15 of the Chart Book on calculating %oob.
Remember, only 2 Callisto applications are permitted each season, not to exceed 16 oz/A product for the season. Many growers will be getting ready for their second fungicide application. These are applied at 10-14 day intervals; try to stay closer to the 10-day interval if possible. If you have fairy ring, ferbam applications are made June-July. This is applied as a soil drench. Fertilizer applications can be made during bloom. If using NPK materials, about 25-30% of the total N is put during bloom. If using a fast/slow combo program, 60% of total N goes out at bloom and if using an NPK/fish program, 30-35% of total N goes out now in the form of NPK.
The last Worker Protection Training workshop for the season will be held at the Cranberry Station on Wed June 29 from 2-4 PM. Call Marty to reserve a spot (ext 20 or firstname.lastname@example.org ). The cost is $5 per person.
The Ent lab reports several calls with growers reporting BHF larvae out on the bog. The larvae are about 0.25” long and counts have been as high as 5 or 6. Do not wait to spray if you have numbers this high. Usually the timing is 2 weeks after the ONSET of flight if using growth regulators like Confirm or Intrepid (and again 10 days later). For other insecticides, including Delegate and Avaunt, apply 10 days after peak flight, which is usually during bloom.
Early cultivars such as BL have reached 50% oob already. See page 15 of the Chart Book on calculating %oob. Timing of this spray is critical. If pressure has been high in previous years and berries are sizing up, spray should occur very soon after 50% oob. Delegate, sprayed only at night when residues can dry by morning, is the compound of choice during bloom. Keep in mind that all insecticides, with the exception of Confirm and Intrepid, are toxic to bees. The timing is 0-7 days after 50% oob for ST and BL and 7-9 days for Howes and EB. Your second treatment (if you are planning on this) goes out 10 days later. Then fruit inspection starts.
I have had a couple of growers mention that they have had good success with controlling poison ivy using a combination sprays of 1.5 oz of Callisto and 1.5 oz of Poast plus an adjuvant (in a gallon of water). The sprays were applied as spot treatments (Poast cannot be chemigated). Most applications were put on late May or so. Control was not total after 1 year of treatment, but growers who have tried this say that the combination significantly reduced the PI patch, especially if applied for at least 2 consecutive years.
Many first fruitworm sprays have gone out already and some growers may be applying their second spray soon. The second treatment goes out about 10 days after the first application, if you are using the standard fruitworm practice. As fruits set, begin inspecting 50 randomly picked berries per acre, with a minimum of 200 berries per piece. Check the guidelines on p. 15 of the Chart Book to determine if another spray is triggered. Additional sprays are based on the number of unhatched, viable eggs found in the fruit. We have heard a couple reports of high weevil numbers. Actara and Belay are your summer generation choices. Both products are highly toxic to bees!! Belay should be applied post-bloom.
Avoid applying pesticides on very hot days and strongly consider the potential of the adjuvant to injure petals when making your decision. Last year, it was reported that combination Poast+Callisto backpack spray that injured new cranberry growth (Stevens). They used 0.5 Poast, 0.5 oz Callisto, and 1-1.5 oz NIS in a gallon of water.
If you see diseased dodder or yellow loosestrife dying, please contact Frank at ext 18 or email@example.com . He wants to collect samples as part of a project funded by CCCGA to investigate possible new mycoherbicides.
Weather conditions forecasted for Thursday, July 14 and Friday, July 15 indicate possible scalding conditions. The UMass Cranberry Station predicts that scald can take place when temperatures are moderately high, humidity is relatively low and there is abundant sunshine.
The biggest issue now has been the several days of heat and the stress that it is placing on the vines (including the possibility of scald mentioned within the past few days). Make sure you keep the vines well watered during periods like this until the heat breaks. Some vines have been showing evidence of vein whitening (see photo). Evital applications were made in the fall and likely, the weather conditions have stressed the vines and caused these symptoms to show. A couple of small fertilizer applications (foliar feed with some micronutrients may be good) may help the vines to recover.
Keep in mind, to apply the equivalent of the highest label rate of Callisto (8 oz/A), use just 1.6 tsp per gallon (this assumes an application rate of 30 gallons of water per acre, which is very reasonable for most ground applicators); 1.6 tsp equivalent to about 0.27 oz. The maximum amount of NIS should be 1.9 tsp (0.32 oz) per gallon or 2.5 TBsp (1.3 oz) crop oil; you can use about 2 oz of Poast per gallon of water to deliver the high-end rate of a 1.5% solution. If this combination is working and there are no application (phytotoxicity) issues, then this is good news. Just be sure your recipe keeps to the rates permitted by the label.
From the Entomology Lab: Keep in mind that Belay is only being recommended for cranberry weevil; it is a better choice than Actara for summer weevil management. You can only apply a total of 19.5 oz/A of Delegate per season. Reminder for those delivering to Ocean Spray: No Sevin (carbaryl) applications can be made after August 1.
People have been calling in to the Ent lab to asked what they can spray for cranberry fruitworm and/or Spag if they can’t use Delegate, Diazinon, Intrepid or Sevin? This is happening for Ocean Spray growers particularly. Lorsban use is not permitted after June 15, Intrepid cannot be used after July 15, and Sevin cannot be used after 8/1. Only 3 sprays of Delegate are permitted and many growers have used all of these by now. Some have used their 2 applications of Diazinon as well. Entrust is a viable option for CFW or Spag control if you fall into this group of growers with limited options. Entrust is the organic version of Spintor and is effective, fast-acting but short-lived. Best if used in systems with short rinse times (6 min or less). Wet residues are highly toxic to bees but dried residues are safe. Spray at night and dry by morning is the best approach. Assail can be used but has a 60-day PHI for OS growers (1-day PHI is listed in the Chart Book). Always check with your handler BEFOREHAND if you have any questions about which pesticides are permissible for your situation.
We still recommend scouting for viable unhatched cranberry fruitworm eggs to determine if extra sprays are needed. We understand that this is a time-consuming process but it is the best IPM tool we have for cranberry fruitworm management at this point in the season. If you still have a Delegate spray available and a Spag issue, now is the time to apply for control. The Ent lab reports high counts of flea beetle in some locations. Again, the best choices are Diazinon and Sevin (but many growers may not have this option), then Belay (good only with low-rinse time systems), and then Delegate (still may only slow them down some).
You cannot spray QuinStar any more this season. The Section 18 expired on July 31st. PHIs for compounds (some of the longer ones): Poast and Lorsban 60 days, Stinger, Ferbam, and Bravo 50 days, Callisto and Ridomil 45 days, and Mancozeb products 30 days.
People are still finding unhatched viable fruitworm eggs in numbers over threshold. But spray options continue to be very limited for most growers. No reports of bad flea beetle or Spag according to the Ent lab.
UMass Cranberry Station • 1 State Bog Road, PO Box 569, East Wareham, MA 02538 • firstname.lastname@example.org • 508-295-2212
The UMass Cranberry Station is part of The College of Natural Sciences.