UCONN IPM: Integrated Pest Management:UConn Grape IPM Message

We are at the pre-bloom stage in most vineyards with many shoots up to 20 inches long and up to 14 leaves out. The recent wet weather has promoted the development and spread of most of the grape diseases that we expect at this time: black rot, downy mildew, powdery mildew, and Phomopsis cane and leaf spot. Examining vines at several sites during June 10 and 11 revealed few symptoms so far except for Phomopsis which has been creeping up to worrisome levels in a couple of vineyards. Everyone must be doing a good job protecting your vines. Be sure that you keep a tight fungicide spray schedule during this period through bloom (7 days if wet-10 days if dry) and make sure you use materials (probably a tank mix of two) that have excellent efficacy against all 4 diseases. Most grape or small fruit recommendations have a table with this info (e.g., The New England Small Fruit Pest Management Guide, pg.102, Table 48). When we get to bloom we have to watch out for Botrytis Rot, too. If all of these diseases are not kept under control through bloom, you could have big problems later. Last week, powdery mildew spores seemed to be slower than expected to mature. This week’s samples, which will be examined over the next few days might be much more mature. Remember that downy mildew can develop explosively in a few days if the inoculum is present, the evening, night and morning temps are moderate, and the leaves are wet. It is a good idea to put up grape berry moth traps, if you have not already.

We are providing disease risk prediction tables for selected sites in southern New England for June. We will upload more of these to the website periodically, and we will update the degree day table. The disease risk tables present predictions, they are not facts. They show what your risks were over the last few days for the given disease, and according to the weather recorded by the weather station at that particular site. Growers at some distance from those sites should take these as general warnings. The tables tell us what we already know: we should have been covered before all the wet weather started, and we hope there will be a break in the rain to get covered again before all the pesticide gets washed off.

The most recent issue of New England Grape Notes has important info about canopy management and petiole tissue analysis for adjusting your fertilizer programs, among other topics.

Information on our site was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.