2003 – Current Pest Report – Visual Observations

Tree Stage for McIntosh trees: 
4/14/03- green tip
4/21/03 – half inch green
4/28/03 – tight cluster
5/5/03 – full pink
5/9/03 – bloom
5/18/03 – petal fall

Visual Observations

Starting August 12, the phone message will be available between 5pm & 8am! 

Phone message available 24 hours a day: 949-1456. Updated Mondays (usually)

8/7/03 – Apple maggot flies are still being caught on red sticky spheres. Apply an insecticide every 14 days until around August 20th.
-White apple leafhopper nymphs are beginning to hatch. It may be necessary for some growers to control them. The biggest problem with leafhoppers is they are a nuisance to pickers. Leafhoppers also get excrement on the fruit that looks like small black/brown spots called tar spots. The spots are larger than flyspeck spots.
– Speaking of flyspeck. I saw my first apple with flyspeck today, and my first apple with sooty blotch on 8/4/03. This could be a bad year for summer diseases! Keep protected with a fungicide.
7/29/03 – I finally got the apple maggot chart made for 2003. Here it is. I’m only catching apple maggot flies where there are unsprayed trees nearby. In most orchards I’m catching very few apple maggot flies. We should be at peak apple maggot fly time now. If it has been 2 weeks since your last insecticide application, apply one soon.
-Rose leafhoppers are starting to become adults now. There are also nymphs present. It may still be useful to spray an insecticide against rose leafhoppers. There will be another generation of rose leafhoppers before they leave apples and return to roses for the winter. Leafhoppers can be controlled with Thiodan, Provado, or Sevin.
– White apple leafhopper second generation nymphs should begin to hatch around August 10th.
– I’m finding more orchards with mite problems. Some have European red mites and others have two spotted spider mites. The red mites cause apple leaves to turn bronze colored, where as the two spotted mites cause the leaves to turn pale, or off color. Two spotted mite damage looks like the tree is lacking nitrogen. At this time of year, Pyramite works best to control red mites. Two spotted mites can best be controlled with Savey or Vendex plus Tactic.
– I haven’t seen any fly speck or sooty blotch damage yet, but I think I will soon. Be sure to keep to your summer fungicide schedule.
7/22/03 – Until my final orchard yesterday, I was finding not many apple maggot flies out yet. Out of 20 traps I caught only 5 apple maggot flies. Then at my final orchard I caught 9 apple maggot flies on only 5 traps. At this same orchard I set up 7 traps in an unsprayed Red Astrachan tree. On these 7 traps I caught a total of 577 apple maggot flies!!!! That’s an average of 82 per trap. Now these flies were caught in an unsprayed setting, so it doesn’t really compare to what is happening in a sprayed orchard. Still, many orchards have abandoned trees very close by, so the chances are that apple maggot flies will move into your orchard. Red Astrachans are especially attractive to apple maggot flies. The fruit is nearly ripe, and the maggot flies just love them. If it has been 2 weeks since your last insecticide application, I recommend you apply another one soon.
Rose leafhopper nymphs are much easier to see this week since most of them are larger. Now is a very good time to scout your leaves for the small, white nymphs. Look on the underside of many leaves. I like to turn a whole branch over and look at many leaves in one location. The spray threshold is 25 nymphs per 100 leaves. Thiodan, Sevin or low rates of Provado will control leafhoppers well at this time. I see rose leafhoppers in only a few orchards. They tend to be in orchards with a lot of wild roses on the edges.
I want to start planning for leaf tissue analysis samples. If you want me to take a sample in your orchard, please call or email me. The cost is about $20 per sample. In most situations, one sample is plenty. 874-2750 or hhf@uri.edu.
7/15/03 – I checked 21 apple maggot fly traps this past week and only caught 4 apple maggot flies. So they are around, but not in great numbers. The spray threshold is an average of 1-2 flies per trap. I expect most growers will apply an insecticide this week against apple maggot flies. Remember half or even quarter rates of insecticide will control apple maggot flies.
7/8/03 – I haven’t checked many apple maggot fly traps, but I have not caught any. Hudson Valley, NY reported catching their first apple maggot fly last week. We are usually pretty similar to Hudson Valley. If you don’t have red sticky spheres to check for apple maggot fly, you may want to apply an insecticide soon. Early maturing varieties should be protected with an insecticide soon. Use half rates of Imidan or Guthion. If you are using red sticky traps you can wait until you have an average of 1-2 apple maggot flies per trap.
– Green apple aphid numbers have been very low this season. In all situations I’ve seen, predators have been controlling the aphids and no insecticide is needed.
– Leafminer adults from the first generation have mostly emerged from the mines by now. If you need to treat for leafminer, now is a good time to apply the first spray of Provado. Since the second generation is much more spread out than the first generation, you will probably need a second application of Provado 10-14 days after the first application.
7/1/03 – Plum curculio is definitely over. I know that UMASS said they were still getting plum curculio migration, but I have not seen any new plum curculio stings after looking in many orchards. I do see fresh plum curculio stings in an unsprayed orchard I’m checking. This is much different because plum curculio will keep laying eggs until the end of July if they are not killed. So as long as you sprayed an insecticide on June 12 or later, you should be all set with respect to plum curculio. It wouldn’t hurt to continue checking fruit for new damage. That way you will be confident that your fruit is safe.
-Hopefully everyone has apple scab under control by now. It seems as though most growers have been able to keep it off the fruit. You should be on your summer schedule now of Captan every 2 weeks or Captan plus Topsin M every 3 weeks. If you are still experiencing too much scab, you could still apply Sovran or Flint to help protect the fruit. You are allowed 4 applications a year.
– All the leafminers mines from the first generation are visible now from the upper leaf surface. It is a good time to check your orchard and see if a treatment is needed against the second generation. The threshold is 13 mines per 100 fruit cluster leaves. You need to count only fruit cluster leaves because these were the leaves available when the leafminer moths were laying eggs way back in April and May. If you reach this threshold, perhaps you should treat with Provado in about a week and again about 10 days later. The second generation is more spread out than the first generation, so two applications of Provado are probably necessary to provide adequate control.
– Green apple aphids are present and so are plenty of aphid predators. I don’t think anyone should need to spray for aphids.
– San Jose scale crawlers may have started to crawl by now. I will check a site this afternoon and let you know what I find. The chemical Esteem should work well against San Jose crawlers. This should be used only if you have a known problem. The red spots from San Jose scale should be showing up on apples in a couple of weeks. Check the picture in your pest management guide if you aren’t sure what they look like.
6/24/03 – If you listened to yesterday’s phone message, then you heard me say that plum curculio season may not be over. I’m happy to report that I mis-read a chart and that we should be beyond plum curculio season. I still advise checking border row trees for fresh injury. Fresh injury doesn’t have any tan, corky, callus tissue associated with it. The wounds are small mushroom shaped slits and tend to be a bit orangey around the edges of the cut. If you find fresh injury you may want to make another insecticide application.
– White apple leafhoppers are starting to fly now. There is probably still time to spray against this pest. Use Thiodan, Provado, or Sevin. The damage is on the older leaves and shows up as white stippling damage on the top side of leaves. If you turn a damaged leaf over, you will probably still see some white apple leafhopper nymphs. The adult white apple leafhopper will lay eggs soon, but these eggs won’t hatch until mid-late August. It is better to control them now rather than waiting to so close to harvest.
– If you are finding adult leafhoppers, but don’t see nymphs or damage, you probably have rose leafhoppers migrating into your orchard. This pest starts out the year on rose and then migrates to apples about this time of year. I don’t think I have seen any this year yet. The rose leafhopper remains on apples for the rest of the summer, having 2 generations before returning to rose to lay eggs to over winter. If you have rose leafhopper adults now, you should wait a couple of weeks and treat the next generation nymphs after they hatch. Again, Thiodan, Provado, or Sevin will control them.
– If you trees are free of apple scab you can switch to a summer schedule of Captan every 2 weeks or Captan plus Topsin M every 3 weeks. If you can find much scab and it turns rainy again, be sure to be protected with a fungicide.
6/17/03 – If you apply an insecticide this week (sometime after 6/13) you should be protected against plum curculio for the rest of the season. If your last spray was before 6/13, you should probably re-apply an insecticide to make sure you control PC through the entire time when they migrate into the orchard.
-In addition to the insecticide, you should apply a full rate of a fungicide, whether or not you have any scab in the orchard.
6/13/03 – Not much new to report. Once it stops raining I expect everyone to re-apply insecticide and fungicide. Scab as well as other diseases are active in most orchards. Plum curculio are expected to continue migrating into orchards and your trees need to be protected. Hopefully it will dry out soon!
6/10/03 – The predicted end of plum curculio migration is 6/21 in the Greenville area, and 6/24 along the coast. You need to have insecticide coverage until the end of plum curculio migration. That means if your insecticide application lasts 2 weeks (if it is not all washed off by rain) then your last plum curculio insecticide needs to be applied on 6/7 or later (or 6/10 or later for the coast). The end of plum curculio season is predicted by predicting the number of expected degree days and this comes from predicting the weather. So, if the weather returns to unseasonably cool conditions, this will delay the end of plum curculio season. This means if it gets too cool, plum curculio will continue to migrate into orchards for a longer period of time. I will continue to update when we think the end of plum curculio season will be.
– Be sure to attend the twilight meeting at Noquochoke Orchard
 in Westport, MA on Thursday, June 12 at 4:30.
6/4/03 – Scab -We are past primary scab season, but I don’t think anyone should switch to a summer spray schedule yet. I have been seeing some apple scab at several orchards and all this wet weather is making it very easy for secondary lesions to form. Continue to keep protected with a fungicide for at least another week. Hopefully by then everyone can switch to summer schedule of using reduced rates of Captan every 2 weeks or Captan plus Topsin M every 3 weeks. I really like the plan of: use Captan, wait 2 weeks, then use Captan plus Topsin M, wait 3 weeks and then spray just Captan again – alternating like this.
– Plum curculio– I was surprised how many plum curculio scars I saw on unsprayed trees yesterday. The scars did not seem very fresh. They were probably made at least 5 days ago. I did find some scars in sprayed trees as well. I think the scars were made after the 2 inches of rain on 5/26 and before the grower sprayed again with insecticide. This cool weather will probably extend the plum curculio season, meaning you’ll probably need to make more applications of insecticides than usual to get adequate control. Use full rates of Imidan, Guthion or Avaunt. If your orchard is large enough to warrant a border row spray, you could now switch to that approach. Spray the outside two rows all around the orchard.
– Leafminers – As I said 6/2 – we are nearing the end of the time to be able to treat for first generation leafminers. I think only AgriMek will be effective now.

6/2/03 – At URI’s East Farm orchard today I found a leafminer mine which had advanced to the tissue feeding stage. This is when the mine is visible from the upper leaf surface as a pucker in the leaf covered with small, white spots. If you are planning to treat for first generation mines, now is the time to apply AgriMek. It is actually bit late to use Provado now. If mines are present, they are mostly visible from the undersides of fruit cluster leaves as small, silvery patches. We use a spray threshold of 13 mines per 100 fruit cluster leaves.
– Also at East Farm today I found summer eggs of European red mites on the underside of Red Delicious leaves. These are the first summer eggs I’ve seen. Miticide choices at this time include AgriMek, Apollo, or Savey.

5/30/03 – Yes, I find scab, but so far it doesn’t look too bad. Another week from now should give us a much better picture of how bad the scab will be. It sounds like we are in for more wet weather this weekend. Ugh.
– I think most growers applied an insecticide against plum curculio this past week. I actually found a scar on an apple yesterday. You know they are ready to attack. If the cool weather persists, it will drag out how long we need to worry about plum curculio. If you applied a full orchard insecticide this week, you can probably switch to spraying just the 2 outside border rows for the rest of plum curculio season. Many orchards in Rhode Island are small and so spraying the 2 outside rows all around the orchard means you cover nearly the whole orchard.
– I saw many leafminer mines in one orchard today. Look now on the underside of leaves for the small, silvery mines. If you find 13 mines per 100 fruit cluster leaves, consider applying Provado or AgriMek.
– European red mites are nymphs and adults now. Soon they will be laying the first generation summer eggs. Apollo, Savey, or AgriMek will still control red mites if applied soon.
5/28/03 – These off and on showers are dreadful for spreading apple scab! I’ve copied some of NY’s Scaffold newsletter about using Captan during periods of extended cloudy weather:

CAUTION WITH CAPTAN (Dave Rosenberger, Plant Pathology, Highland) Fruit growers should be very cautious about using captan during the next 7-10 days because weather conditions over much of the state have left apples, peaches, plums, and cherries unusually susceptible to captan injury. Captan is an effective, broad-spectrum fungicide that is labeled for many fruit crops. However, when absorbed into plant tissue, captan causes phytotoxicity that appears as leaf spotting, shot-holing, and leaf yellowing. When combined with other products that enhance uptake into leaves, captan applied at this time of year can cause complete defoliation of peach and nectarine trees. To be safe, growers should avoid applying captan until trees have had several days of sunny, dry weather.

The risk of captan injury is greatest when the annual spring growth flush of fruit trees coincides with an extended period of cloudy, cool, damp weather. The growth flush on fruit trees begins when terminal shoots start growing during or shortly after bloom. The cuticle (the waxy layer on the leaf and fruit surfaces) develops in response to heat and water stress. During cloudy and damp weather, there is little danger from heat or water loss and trees therefore produce only a thin cuticle to protect the newly formed leaves and enlarging fruitlets.

The same waxy cuticle that serves to prevent water loss also prevents captan from entering and injuring living cells beneath the plant cuticle. Some varieties of plums and cherries almost always develop a leaf spot or shot-hole after captan is applied because, even under the best conditions, some captan enters and kills leaf cells of these varieties. For most other fruit crops, captan causes little or no injury except during unusual seasons when weather conditions inhibit cuticle development.

Even when plant tissue has only a thin cuticle, captan by itself will rarely cause phytotoxicity (except to those plum and cherry varieties that are especially susceptible to captan injury). Problems often arise, however, when captan is mixed with other agrichemical products. Spray adjuvants that enhance the transport of captan through the plant cuticle can greatly increase the phytotoxicity of captan, especially when the plant cuticle is thin at the time spray is applied. Adjuvants that enhance uptake of captan include spray oils, some spreader-stickers, and other petroleum-based carriers commonly found in products that are formulated as liquids or emulsifiable concentrates.

Where apple scab symptoms are appearing in orchards, the best option for stopping further spread of apple scab is to apply a combination of an SI fungicide along with the maximum label rate of captan. To avoid phytotoxicity problems, however, growers may need to use an SI-plus-mancozeb combination for the next week to avoid the potential phytotoxicity that could result if captan is applied at this time. This is especially true if Sevin XLR Plus will be applied for thinning or if spray oil will be applied with a miticide during the next week. Those who opt to apply captan despite the risks are advised not to use spray adjuvants that might enhance trans-cuticular movement of captan.

Scaffolds always says something interesting. The newsletter is published Mondays and you can have them email it to you or simply go onto the Scaffolds website.

This wet weather is giving cedar apple rust a good opportunity to cause problems. The orange galls on eastern red cedars release spores during rainy periods from April up until about mid-June. These spores land on apples and cause the characteristic orange lesions. Golden Delicious, Mutsu and Cortlands are particularly susceptible to cedar apple rust. Effective fungicides include Rubigan, Nova, Procure, Manzate, Polyram, and Dithane. Rusts can not be managed with post-infection sprays.
5/27/03 – I’ll write more tomorrow. The short message is spray a fungicide soon. I’m finding at least a little scab in most orchards. Even though we may be at the end of primary scab season, you’ll need to keep your trees protected for at least the next two weeks. It takes about 2 weeks for lesions to start appearing once an infection period has occurred. With all the rain we received on Monday, 5/26, there is probably very little fungicide still on the foliage and fruit.
– If you have applied a post bloom insecticide, you can probably put off spraying another insecticide until warmer temperatures are forcasted (70’s). If you have not applied a post bloom insecticide it is probably best to apply one soon.
5/23/03 – Ugh! This horrible weather continues. Spray a fungicide as soon as you can! If you see much scab in your orchard, spray Sovran or Flint.
5/22/03 – What a big ugly infection period we are experiencing. It started yesterday mid-day and is continuing right through tonight and ending???????
– It makes a lot of sense to spray fungicides now, but leave out the insecticide until the weather warms up. Plum curculio and other insects are not active in this weather. Remember, plum curculio won’t attack the fruit until the fruit measure 9mm in diameter.
5/18/03 – I think we had one large infection period last week from 5/12-5/14.
– The next wetting period (rain event) could release the last of the primary scab spores for the season. This is not the case if your orchard is near the coast and have not reached petal fall. Orchards in cooler regions will reach the end of primary scab season about one week after petal fall.
– I started seeing a lot of apple scab lesions on 5/15. Check your trees now. If you find more than a little bit of scab, spray Sovran or Flint now.
– Ron Prokopy from UMASS says that plum curculio won’t attack apples until they are 9mm. That information in combination with the cool forcast probably means you can delay your petal fall insecticide for several days.

5/12/03 – 
Today’s weather is probably causing another apple scab infection period. Even though we did not get much rain, there are puddles on some leaves that have been wet all day. Spores would have been released this morning after last night’s rain.
– Every few days we have had an infection period. Many growers may be in trouble with scab! I did see two tiny lesions on an unsprayed tree today. They were on the oldest cluster leaves. The lesions are probably from our first infection period on April 22. It has taken this long for the lesions to appear. If you do find lesions between now
 and petal fall, you may want to apply Sovran or Flint to try to burn out the lesions.
– This cold weather has perhaps discouraged leafminers from laying many eggs. I only see large number of eggs in one orchard. Laefminers can be controlled at petal fall with Provado or AgriMek at first cover. AgriMek has the estra bonus of controlling mites. Remember AgriMek must be mixed with oil or an adjuvant.
– I did see a few newly hatched white apple leafhopper nymphs today. If you have had trouble with white apple leafhopper in the past you can spray at petal fall withThiodan or Provado. Provado will probably be effective at very low rates (like 1 oz. per 100 gal).

– I started catching European apple sawflies on white sticky traps. Sawflies can easily be controlled at petal fall with Imidan or Guthion.
 – We are sure in a wet weather pattern. We’ve had two infection periods, one on May 6th and another one today, May 8. Apple scab is at its peak now – so be well prepared.
– I spent the day on Aquidneck Island and in Little Compton. Apple trees there are about 7 days behind the Greenville area. Most trees are between tight cluster and early pink. I did find hatched European red mite eggs as well as Z. mali predators. This makes me think that European red mites started hatching in the Greenville area around May 1st.
– I found many leafminer eggs at one orchard (about 5 eggs per cluster). As I stated 5/5, leafminer eggs are laid on the underside of leaves and look like small clearish blobs. You have to use a magnifier to see them. Finding 13 eggs on 100 cluster leaves could be used as a threshold. (That’s 100 cluster leaves, not 100 clusters). I did see one hatched leafminer egg today. Chemical control options include Provado at petal fall, AgriMek at first cover, or Assail (though I don’t know the timing – but I will find out).
5/5/03 – Tarnished plant bugs. I caught many tarnished plant bugs on traps today. I found 18 on one trap in an orchard of dwarf trees, though many other traps have none. In orchards with many plant bugs, Imidan applied at pink will control them.
– Leafminers. Leafminer trap captures have exceeded the pink threshold in some orchards. I started seeing leafminer eggs today. They can be found on the underside of leaves and look like small, pale blobs. Leafminer mines can be controlled after petal fall.
– European red mite egg hatch is well under way. I also found many Z. mali mite predators in some orchards. In one orchard I also found many pest yellow mites, which I’ll watch closely.
5/4/03 – For those of you that had a shower on Tuesday afternoon, April 29, and it stayed wet through the night – it was the third infection period. We had a fourth infection period on Thursday, May 1st. I’ll have more to report on Monday, May 5th.

– We had our second apple scab infection period on April 26.
– A lot of growers were out spraying this morning so I didn’t check many insect traps today. We are above the threshold of 8 leafminers per trap at URI’s East Farm orchard.
– It will still be at least another week before apple scab lesions start to appear on leaves from the 4/22 infection period.
– Now is the best time to apply dormant oil for European red mites. Reduce oil to 1.5 gal/100 gal water.
– If you were not well protected from either apple scab infection period, consider applying Rubigan or Nova at the full label rate.
4/22/03 – First apple scab infection period of the season. Caught a few more leafminer adults on red traps at URI’s East Farm (10 on 3 traps).
4/21/03 –
 We haven’t had an apple scab infection period yet, but that could quickly change tomorrow (Tuesday). Rain is expected with temperatures in the high 40’s. At 48 degrees only 12 hours of wet leaves are needed to cause an infection. Most growers have applied a protectant fungicide. For those of you that have not, a fungicide with kick-back action will be required as soon as it is possible. In Massachusetts and New York, apple scab spores are ahead of schedule. More apple scab spores are probably ready to be released now, than would normally be ready at half inch green.
– Caught our first leafminer adult on a red sticky trap. Only caught one adult on 30 traps checked
. If you have traps, set them out now or it will be too late to use them accurately.
– Caught several tarnished plant bugs today in white sticky traps. One orchard had an average of 3 per trap. The threshold by tight cluster is 5 per trap.

4/16/03 –
 trees have advanced rapidly during these two days in the 70’s. Since green tissue is available, the threat of apple scab is real! Apply protectant fungicides soon.
– Caught 2 tarnished plant bugs on one white sticky trap in one orchard. I’ve only checked traps in 3 orchards so far. Tarnished plant bugs are not a problem at this time. For many years, we havenot had a problem with tarnished plant bugs.
– No leafminer caught on red sticky traps yet.
-I plan to start the recorded pest message on April 21st (949-1456)