As of June 27, Sparganothis has accumulated 968 DD. Based on the DD model, Sparganothis has reached peak flight, and should have started egg laying. 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.
Archives for June 2016
June 28, 2016 Andy Wyenandt
Dickeya dianthicola affecting potato growers throughout Mid-Atlantic region – Updated 7/5/16
In addition to Dickeya dianthicola being found in ‘Reba’, ‘Snowden’, and ‘Norwis’ on 3 farms in New Jersey this year, the pathogen has also been detected in fields with seed originating from Maine on 5 farms on Long Island in ‘Reba’, ‘Vivialdi’, ‘Superior’, ‘Norwis’, and ‘Waneta’ and three fields of ‘Vivaldi’ in DE. The pathogen has been detected in PA, MD, VA, NC, WV, and FL this summer on seed from Maine and New Brunswick, Canada (NJ and VA). Maine potatoes are currently shipped to over 20 states across the country (CA, CT, FL, ID, IN, KY, MD, MA, MS, NH, NJ, NY, NC, OH, PA, RI, TN, VT, VA, WA, WV, and WI). Potato growers, crop consultants, and Extension personnel in states which grow Maine potatoes should remain vigilant by scouting their fields for Dickeya symptoms on a regular basis and by submitting any suspect samples for diagnostic testing. Dickeya dianthicola has been detected in the US in the past, and because of this, APHIS just recently announced that the pathogen has been designated as a non-reportable/non-actionable pathogen despite its potential to cause 100% crop loss. A link to the USDA/APHIS website for information on Dickeya dianthicola detection and control can be found here.
For more information on Dickeya please see the following articles posted online – source(s) of information:
Update on Dickeya detections in potato – University of Delaware
Dickeya Blackleg: New potato disease causing major impact. – Cornell University
Watch for Dickeya – a new potato disease – The Ohio State University
High security Aroostook farm advances tater technology. – Maine Potato Board
Slowing Dickeya, other pathogens in Canada. – North Dakota State University
Dickeya: A new threat to potato production in North America. – SPUDsmart
Dickeya is coming. – University of Wisconsin/North Dakota State University
Maine ‘Ground Zero’ for new potato disease. – Maine Department of Ag.
Maine seed potato growers looking to protect brand against disease. Maine Department of Ag./Maine Potato Board
June 27, 2016 A.Wyenandt, W.Kline, and J.Ingerson-Mahar
Potato | Tomato Disease Forecast 6-28-16
Click to View | Download Report 6-28-16
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.
June 27, 2016 Andy Wyenandt
Dickeya discussion at National Plant Board meeting in Wilmington, DE
The National Plant Board will be holding their annual meeting in Wilmington, DE on July 31 to August 4th. The National Plant Board plays a significant leadership role in regulation and policy rules in agricultural production with each state having a representative member. One of the topics of discussion will be Dickeya dianthicola which has caused significant problems in potato production in NJ other states in the mid-Atlantic region. There will be presentations on Dickeya and seed potato production on the morning of Wednesday August 3rd starting at 8:15 AM. More information on the meeting and the schedule can be found here.
June 24, 2016 A.Wyenandt, W.Kline, and J.Ingerson-Mahar
Potato | Tomato Disease Forecast 6-25-16
Click to View | Download Report 6-25-16
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.
June 24, 2016 Andy Wyenandt
Dickeya dianthicola affecting potato in New Jersey
Dickeya dianthicola, an aggressive form of blackleg, has been found on potato in New Jersey for a second year in a row. The pathogen has also been found in potato crops in other states in the mid-Atlantic region this summer. The pathogen can cause significant losses if brought into the field on infested seed. Symptoms of Dickeya include the rotting/melting of the infested seed piece without the smell of traditional soft rotting bacteria. The bacterium will spread to other tubers developing on plant and into the stems leading to blackleg symptoms on the foliage. Infected plants can collapse quickly under hot conditions. Surveying and testing for Dickeya is currently being done in all states in the region. All potato growers should scout on a daily basis and any suspect plants should be submitted for testing. In New Jersey, fields of ‘Reba’, ‘Snowden’, and ‘Norwis’ have tested positive for Dickeya dianthicola from seed originating from Maine and Canada.
Symptoms of blackleg caused by Dickeya dianthicola on an infected potato plant.
