Contents

Upcoming meetings

April 19, 20, 21: Tree fruit twilight meetings

May 17, 18, 19: Tree fruit twilight meetings

June 14, 15, 16: Tree fruit twilight meeting

Mark you calendar for the above twilight meeting dates. Location and time TBA.

The way I see it

This pre-season Healthy Fruit issue is being mailed to everyone who subscribed in 2010. NOTE, however, that this will likely be your LAST ISSUE OF HEALTHY FRUIT for 2011 unless you renew your subscription by filling out and sending in the enclosed mail-in form with your information and $ remittance. ($50 for e-mailed Healthy Fruit, $70 for postal mail.) Any questions about the status of your subscription, let us know.

The main thing I want to bring to your attention is that the 2011 New England Tree Fruit Management Guide is available, and can be ordered using the same mail-in form with a personal check. Be sure to get yours before the season starts.

Other things that have been on my mind (among many others) include:

Brown marmorated stink bug, BMSB, we will keep a close eye on that. You should too and educate yourself. Here is a good site to help you keep on the lookout and for identification of BMSB: http://njaes.rutgers.edu/stinkbug/identify.asp. Also see 'A Summary of Brown Marmorated Stink Bug Damage in New Jersey Fruit Crops -- 2010' in Fruit Notes.

Winter moth affects only near-coast locations. (You probably know who you are.) Sonia Schloemann and Bob Childs have written a nice fact sheet on winter moth and blueberry. You can apply the recommendations and control approach therein, as long as the product is labeled for apple. My personal approach would be a pre-bloom (usually around tight-cluster) application of Dipel with a low rate of pyrethroid.

San Jose scale, seems to be increasing year-to-year. Probably a result of reduced organophosphate use and skipping oil spray(s). Including Lorsban with your spring oil is a good way to get rid of scale if you are seeing it. See my updated article 'Do You Know the Way to San Jose' on the UMass Fruit Advisor for more information.

J. Clements

2010 New England Tree Fruit Management Guide available

As a reminder, the 2011 New England Tree Fruit Management Guide is available for purchase here:

http://www.umass.edu/fruitadvisor/2011/2011netfmg.html

The 2011 New England Tree Fruit Management Guide (NETFMG) is available NOW. For $50 you will receive the printed guide by postal mail. You can download and print a mail-in form to order the NETFPMG by personal check here.

Note that for 2011 the herbicide/weed control section has been completely revised, and all sections have been carefully reviewed for changes in 2011. Order yours today!

Also note that Commonwealth Quality produce certified growers should have the 2011 NETFMG in their possession to achieve the maximum score!


Orchard diseases -- starting with a clean slate

It’s hard to overemphasize how important it is to start with as clean a slate as possible when talking about orchard diseases. The pathogens that cause scab, fire blight, brown rot and other diseases are coming off the toughest part of the year for them. They had to get through the winter, and at this point their numbers are as low as they get. And now’s the time to get them even lower.

One of the things that enable the fungi and bacteria that cause apple diseases to succeed is their ability to reproduce. Under the right conditions, their numbers can grow from a few thousand to hundreds of millions in a matter of a few days, or for bacteria a few hours. One of the things that can keep their numbers from exploding to dangerous levels is minimizing them at the start of the season.

It’s not too late to reduce apple scab inoculum in orchards, but time is getting short. The best time to chop leaves or treat them with urea is two to three weeks before green tip. As the time between green tip and leaf litter treatment gets shorter, the effectiveness of the treatment drops.

Here are treatment recommendations from UMass Fact Sheet F-134-2009, “Reducing Apple Scab Risks and Saving Scab Sprays." (http://www.umass.edu/fruitadvisor/factsheets/f134.html)

  • Shredding leaves. Shredding all leaves on the orchard floor in November or late March or April reduces the number of scab spores by about 85%. If the strip under trees cannot be reached with shredding equipment, then flail chopping the remaining area between trees will reduce scab spores by about 50%. Small leaf pieces break down quicker, and are more readily consumed by earthworms. If shredding is done in April, it will flip leaves, and leaf pieces, over. The scab fungus has already started to grow by the spring, and forms fruiting structures that will release spores up and into the air. Flail chopping flips probably about half the leaves or pieces over, and spores formed in those pieces of leaves cannot release into the air.
  • Urea treatments. Spraying the surface of the leaves on the ground with urea will reduce spores by about 66%. Use feed grade urea, which is 46% N, and mix a 5% solution in water. (This is 44 lb. per 100 gal.) Feed grade urea is more expensive but dissolves in water much easier than granular (fertilizer grade) urea. Thus, feed grade is recommended, though the cost is higher – app. $20/acre vs. half that price for granular urea. The nitrogen content of both is the same, so granular urea can be used, but with more effort. Spray the ground surface at a rate of 100 gal. per acre. You can use an air-blast sprayer with only the lower nozzle(s) turned on, but it’s best to use a boom-type herbicide or field crop-type sprayer. Make applications approximately two to four weeks before bud break, with a longer interval being more effective. Consider that this supplies app. 20 lbs. actual nitrogen per acre, so you will need to adjust your N fertilizer application rates later in the season.

A silver tip to green tip application of copper to apples helps on two fronts, and maybe more. First and foremost, it’s a must for fire blight management. Regardless of whether there has been fire blight seen in a block in the last year or three, copper will reduce the amount of fire blight bacteria that have overwintered in an orchard. There are always some present. The key is to keep their numbers below dangerous levels, and spring copper is the first step in the annual management program.

Second, copper will offer some early-season scab protection. The effective life of copper against scab is only about 5 to 7 days, and in high inoculum blocks it should be used with another fungicide. Finally, it has been suggested that early-season copper helps with nutrition and cold hardiness. It delivers copper to new green tissue at a time when it is very helpful. And it may kill ice nucleating bacteria that can damage tissue during heavy frosts.

A dormant copper spray on peaches can control leaf curl (a fungal disease caused by Taphrina deformans), and can help with bacterial canker (caused by Pseudomonas) and may reduce inoculum for bacterial spot (Xanthomonas) later in the year, and should be applied just before bud swell in the spring. (If not applied the previous fall.) Note it has to be dormant -- once the peach leaves break bud the infection has already occurred. Chlorothalonil also is very effective.

There are many formulations of copper fungicides available. Check label rates, because too high a rate can damage peaches. As a reference, COCS and Kocide are both recommended at 4 lbs. per 100 gal. before bud break.

Brown rot mummies should be removed, ideally, in the summer after harvest. But if not, getting them out now during pruning is very important. These mummies rain spores on flowers in the spring.

It’s tempting to skip pre-bud break sprays. After all, they don’t appear to have any direct effect. It will be weeks before fire blight or scab symptoms even begin to appear. But these applications can help insure that those diseases won’t show up.

A final note: put these applications on as dilute as possible. Microbes are called that for a reason. They’re microscopic and hide in crevices we can’t even see. So it’s important to get chemicals into those cracks and crannies to kill them. Go slowly and go dilute.

D. Cooley

Useful links

UMass Fruit Advisor http://www.umass.edu/fruitadvisor/

Scaffolds Fruit Journal http://www.nysaes.cornell.edu/ent/scafolds/

Network for Environment and Weather Applications (NEWA)

JMCEXTMAN Blog http://jmcextman.blogspot.com/

Follow me on Twitter http://twitter.com/jmcextman and Facebook http://www.facebook.com/jmcextman

The next Healthy Fruit will be published April 5 or thereabout, 2011. As always, feel free to get in touch with any member of the UMass Fruit Team if you have questions or comments.