Archives for June 2016

Veg IPM Update: Week Ending 6/22/16

Sweet Corn

16ecb0622European corn borer (ECB) moth catches are very low now.  The first flight is largely over, and as is common, feeding signs in the field have increased as eggs hatch.  Present adult activity is largely confined to Gloucester and parts of surrounding counties (see ECB map).  Larval feeding ranges from single digits to 40% in areas where IPM personnel are operating, although many plantings still have no detectable feeding at all.  The highest feeding percentages are currently in Mercer and parts of Morris counties.  Be sure to begin monitoring plantings for ECB feeding while they are still in the whorl stage.  Consider treating when the number of infested plants in a 50 plant sample exceeds 12%.  Feeding in the whorl stage will appear as numerous small holes (called “shot-hole”) on leaves, with damage present on consecutively younger leaves. As plants progress to pre-tassel and beyond, droppings and  larvae may be found in or on the emerging tassels (see ecb in tasselphoto at right).  Any planting remaining at or above threshold as it proceeds to full tassel should be treated, as this is the last stage at which ECB larvae will be exposed and vulnerable to insecticidal sprays.    Insecticides that are acceptable in organic production include the spinosyn based material Entrust (IRAC-5) and Dipel (IRAC-11a).  The 10G formulation of Dipel is particularly useful when granules can be dropped or broadcast such that they get into the whorls of corn plants.  Other effective insecticides include Coragen (IRAC 28), and the synthetic pyrethroids (IRAC 3).  See the 2016 Commercial Vegetable Recommendations Guide for a more complete list of insecticides.  [Read more…]

Sparganothis Fruitworm Degree-Day Update: as of June 21, 2016

Based on our degree-day model for Sparganothis fruitworm, flight initiation was predicted around 595

Life history benchmarks for Sparganothis fruitworm and associated degree-day estimates (credit: Elissa Chasen and Shawn Steffan, USDA-ARS and UW Entomology).

Life history benchmarks for Sparganothis fruitworm and associated degree-day estimates (credit: Elissa Chasen and Shawn Steffan, USDA-ARS and UW Entomology).

DD, and indeed, Sparganothis flight begun in Chatsworth, NJ, the week of June 6. As of June 21, Sparganothis has accumulated 839 DD. Based on the DD model, Sparganothis peak flight is predicted by the end of this week (884 DD). Although moths should have begun laying eggs, these eggs should not be hatching until early next week (895 DD). Reminder that a single insecticide application, i.e., post-bloom application with Delegate, Altacor, Diazinon, or Intrepid, aimed at Sparganothis larvae will likely have the greatest effect if it is timed for peak egg-hatch/larval-emergence, which is approximately 1,400 DD. I will keep you updated on these predictions as the season progresses.

Sparganothis fruitworm Adult

Sparganothis fruitworm Adult

Fruit IPM for 6-21-2016

Brown Marmorated Stink Bug being found in traps with low levels of damage in the field. Starting Spotted Wing Drosophila treatments in blueberries. Grape Berry Moth treatments due by the end of the week in southern counties. View the full update for 6-21-2016.

Vegetable Disease Briefs – 6/21/16

  • Cucurbit downy mildew has been reported on cucumber as far north as northern North Carolina this past week. CDM was reported on acorn, yellow summer, and butternut squash in South Carolina and on watermelon and cucumber in North Carolina. All cucurbit growers should scout on a regular basis for downy mildew and powdery mildew.
  • There have been no new reports on late light in the region. Late blight (US23) was reported on potato on the Eastern Shore a few weeks ago. All tomato and potato growers in the region should scout on a regular basis.
  • Blackleg caused by Dickeya dianthicola has been reported in potato this past week. All potato growers should continue to scout for symptoms of Blackleg, especially as temperatures warm up, and report any suspect plants or fields for testing.

 

Fruit IPM for 6-14-2016

Starting second generation of oriental fruitmoth in peaches. Starting SWD programs in blueberries. View the full update for 6-14-2016.

Potato | Tomato Disease Forecast 6-20-16

Click to View | Download Report 6-20-16

Potato Disease Forecasting Report

We will be tracking DSVs for Late blight development and calculating P-days for initiating the first early blight fungicide application.

The first late blight fungicide application is recommended once 18 DSVs accumulate from green row. Green row typically occurs around the first week in May in southern New Jersey. An early season application of a protectant fungicide such as mancozeb (Dithane, Manzate, Penncozeb) or Bravo (chlorothalonil) as soon the field is accessible is suggested. Please be vigilant and keep a look out for suspect late blight infections on young plants. No late blight has been reported in our region to date.

Remember the threshold for P-days is 300!  Once 300 P-days is reached for your location early blight fungicide applications should be initiated. Growers who are interested in using this model should chose the location above that is closest in proximity to their farming operation and should regularly check the Cornell NEWA website (http://newa.cornell.edu/) where this information is compiled from. Click on Pests Forecasts from the menu, select your weather station, and click on tomato diseases, set accumulation start date and a table of daily and total DSVs will be generated.

Tomato Disease Forecasting Report

Disease severity values (DSVs) for early blight, septoria leaf spot, and tomato anthracnose development are determined daily based on leaf wetness (due to rainfall, dew) and air temperature.

On a daily basis DSV values can range from 0 to 4 where 0 = no chance for disease development to 4 = high chance for disease development.
DSVs are accumulated during the production season.

Fungicide applications are based on an individually determined DSV threshold. The first fungicide application for the control of these three diseases is not warranted until 35 DSVs have accumulated from your transplanting date. After that, growers can base fungicide applications on different DSV thresholds.