Allium leaf miner update: 03/25/24

Allium Leaf Miner (ALM)

Many weather stations on the NEWA network except for typical colder sites in northern New Jersey have surpassed 250 growing degree days (GDD) base 39˚F.  39˚F is close to the lower developmental temperature (38.3˚ F) which our colleagues at Penn State recommend for predicting the first emergence of ALM adults.    In recent years, initial feeding/egg laying scars have been detected within a few days of local weather stations recording the 250 GDD threshold.  Growers who feel they may be impacted by this pest should check the accumulated GDD from local weather stations.   Growers in southern counties may reasonably assume there will be ALM activity in their area soon, if not already happening.  To determine GDD from local weather stations, the NEWA website https://newa.cornell.edu/ is very helpful.  From the NEWA home screen, select the nearest weather station from drop down menu at the center of the page.  Next, scroll down to “Weather Tools” on the right side of the page, and select “DD Calculator”.  Select your start date (1/01/24) and end date as well as Degree Day Type (39 F) from the menu at the left of the page.  The site will automatically generate the accumulated GDD base 39F to the last day of your requested sample, and then offer a forecast of accumulated GDD for the next week.   If you should select 1˚C, then the DD accumulation should be 350.

Deceased tree branch

Photo: Sabrina Tirpak. Allium leaf miner oviposition scars on onion

Growers should consider initiating the control method of their choice at this time, if any allium crops are in the field.  Affected crops include chives, scallions, garlic, onions and leeks.  Look for neat rows of white spots descending from the upper tips of allium leaves (see photo at left).  Initial injury often occurs on the tallest leaves.  Under warmer, less breezy conditions, adults may be seen near the tips of leaves (see photo of adult at lower right).  Perennial chive beds are often the first, and most heavily infested alliums of the spring season, so this makes chives an ideal crop to confirm ALM adult activity.

Floating row covers, kept on until this flight ends will help minimize access to plants.  Insecticide applications targeting adults may be helpful as well, although frequency of applications is uncertain.  Spinosyn materials (Radiant, Entrust (OMRI approved)), pyrethroids (Mustang Maxx, Spider on leafWarrior), neonicotinoids (Scorpion, Venom), the diamide Exirel (section 2ee recommendation) and the insect growth regulator Trigard are labeled for miner control.

Adult activity and observations of feeding will be reported on in the IPM Update as they occur.

 

 

 

Allium leaf miner update: 04/06/23

Allium Leaf Miner (ALM)

Allium leaf miner feeding and egg laying injury was discovered on chives and garlic near Milford in Hunterdon County on Wednesday.  All weather stations on the NEWA network except for a few in the highest elevation sites in northern New Jersey have surpassed 250 growing degree days (GDD) base 39˚F.  39˚F is close to the lower developmental temperature (38.3˚ F) which our colleagues at Penn State recommend for predicting the first emergence of ALM adults.    In recent years, initial feeding/egg laying scars have been detected within a few days of local weather stations recording the 250 GDD threshold.  Growers who feel they may be impacted by this pest should check the accumulated GDD from local weather stations.   Growers in southern counties may reasonably assume there will be ALM activity in their area soon, if not already happening.  To determine GDD from local weather stations, the NEWA website https://newa.cornell.edu/ is very helpful.  From the NEWA home screen, select the nearest weather station from drop down menu at the center of the page.  Next, scroll down to “Weather Tools” on the right side of the page, and select “DD Calculator”.  Select your start date (1/01/23) and end date as well as Degree Day Type (39 F) from the menu at the left of the page.  The site will automatically generate the accumulated GDD base 39F to the last day of your requested sample, and then offer a forecast of accumulated GDD for the next week.

Deceased tree branch

Photo: Sabrina Tirpak. Allium leafminer oviposition scars on onion

Growers should consider initiating the control method of their choice at this time.  Affected crops include chives, scallions, garlic, onions and leeks.  Look for neat rows of white spots descending from the upper tips of allium leaves (see photo at left).  Initial injury often occurs on the tallest leaves.  Under warmer, less breezy conditions, adults may be seen near the tips of leaves (see photo of adult at lower right).  Perennial chive beds are often the first, and most heavily infested alliums of the spring season, so this makes chives an ideal crop to confirm ALM adult activity.  At the Milford site this week, chives had feeding/egg laying scars on nearly 30% of leaves.  The garlic field, which was approximately a half mile away, exhibited only 2% infested plants.  A primary reason for this lower infestation rate in the garlic is that allium crops had not been grown in that field for several years.

Floating row covers, kept on until this flight ends will help minimize access to plants.  Insecticide applications targeting adults may be helpful as well, although frequency of applications is uncertain.  Spinosyn materials (Radiant, Entrust (OMRI approved)), pyrethroids (Mustang Maxx, Spider on leafWarrior), neonicotinoids (Scorpion, Venom), the diamide Exirel (section 2ee recommendation) and the insect growth regulator Trigard are labeled for miner control.

Adult activity and observations of feeding will be reported on in the IPM Update as they occur.

 

 

 

Allium leaf miner update: 03/09/23

Allium Leaf Miner (ALM)

Allium leaf miner feeding and egg laying injury was reported on chives in southern Cape May County on Thursday.  The West Cape May weather station (closest station) has recorded 295 growing degree days (GDD) base 39˚F as of Thursday.  39˚F is close to the lower developmental temperature (38.3˚ F) which our colleagues at Penn State recommend for predicting the first emergence of ALM adults.  295 GDD at this temperature is in excess of the 250 GDD base 38.3˚ F that is the threshold for adult emergence and activity.   In recent years, initial feeding/egg laying scars have been detected within a few days of local weather stations recording the 250 GDD threshold.  Growers who feel they may be impacted by this pest should check the accumulated GDD from local weather stations.   Growers in southern counties may reasonably assume there will be ALM activity in their area soon, if not already happening.  To determine GDD from local weather stations, the NEWA website https://newa.cornell.edu/ is very helpful.  From the NEWA home screen, select the nearest weather station from drop down menu at the center of the page.  Next, scroll down to “Weather Tools” on the right side of the page, and select “DD Calculator”.  Select your start date (1/01/23) and end date as well as Degree Day Type (39 F) from the menu at the left of the page.  The site will automatically generate the accumulated GDD base 39F to the last day of your requested sample, and then offer a forecast of accumulated GDD for the next week.

Plant stem

Photo: Sabrina Tirpak. Allium leafminer oviposition scars on onion

Growers should consider initiating the control method of their choice at this time.  Affected crops include chives, scallions, garlic, onions and leeks.  Look for neat rows of white spots descending from the upper tips of allium leaves (see photo at left).  Initial injury often occurs on the tallest leaves.  Under warmer, less breezy conditions, adults may be seen near the tips of leaves (see photo of adult at lower right).

Floating row covers, kept on until this flight ends will help minimize access to plants.  Insecticide applications targeting adults may be helpful as well, although frequency of applications is uncertain.  Spinosyn materials (Radiant, Entrust (OMRI approved)), pyrethroids (Mustang Maxx, Spider on leafWarrior), neonicotinoids (Scorpion, Venom), the diamide Exirel (section 2ee recommendation) and the insect growth regulator Trigard are labeled for miner control.

Adult activity and observations of feeding will be reported on in the IPM Update as they occur.

 

 

 

REMINDER – Vegetable Research Plot Tour at RAREC Tonight

Wednesday, August 24, 2022, 4:30 pm (meet at the shelter near the parking lot)

Rutgers Agricultural Research & Extension Center

121 Northville Rd., Bridgeton, NJ (Upper Deerfield)

PESTICIDE CREDITS approved for this event:  

1A  (AGRICULTURAL PLANT)                     – 07
10  (DEMONSTRATION & RESEARCH)      – 07
PP2  (PRIVATE APPLICATOR CATEGORY)   – 07

4:30 – Welcome and Intros – Rick VanVranken, Atlantic County Agricultural Agent

5:00 –  8:30 pm Tour of research plots and discussions with Rutgers Extension Specialists

Thierry Besancon, PhD, Extension Weed Specialist for Specialty Crops

  • Cover-Crops for Row Middle Weed Management in Plasticulture Tomato.
  • Cover-Crops for Row Middle Weed Management in Plasticulture Cucumber.
  • Crop Safety of Delayed Preemergence Herbicide Application for Cole Crops (Broccoli and Cabbage)

Andy Wyenandt, PhD,  Specialist in Vegetable Pathology

  • Bacterial Leaf Spot Development in Pepper and Tomato in NJ
  • Copper Resistance Development in Bacterial Leaf Spot
  • Basil Downy Mildew Breeding Program Update
  • Bell and Non-bell Phytophthora Tolerance Trials

Joe Ingerson-Mahar, PhD, Vegetable IPM Coordinator

  • Comparing the response of corn earworm to GMO and non-GMO sweet corn varieties and the resistance to BT corn

 

2022 Annual Vegetable Twilight Meeting & Research Tour

Wednesday, August 24, 2022, 4:30 pm (meet at the shelter near the parking lot)

Rutgers Agricultural Research & Extension Center

121 Northville Rd., Bridgeton, NJ (Upper Deerfield)

PESTICIDE CREDITS approved for this event:  

1A  (AGRICULTURAL PLANT)                     – 07
10  (DEMONSTRATION & RESEARCH)      – 07
PP2  (PRIVATE APPLICATOR CATEGORY)   – 07

4:30 – Welcome and Intros – Rick VanVranken, Atlantic County Agricultural Agent

5:00 –  8:30 pm Tour of research plots and discussions with Rutgers Extension Specialists

Thierry Besancon, PhD, Extension Weed Specialist for Specialty Crops

  • Cover-Crops for Row Middle Weed Management in Plasticulture Tomato.
  • Cover-Crops for Row Middle Weed Management in Plasticulture Cucumber.
  • Crop Safety of Delayed Preemergence Herbicide Application for Cole Crops (Broccoli and Cabbage)

Andy Wyenandt, PhD,  Specialist in Vegetable Pathology

  • Bacterial Leaf Spot Development in Pepper and Tomato in NJ
  • Copper Resistance Development in Bacterial Leaf Spot
  • Basil Downy Mildew Breeding Program Update
  • Bell and Non-bell Phytophthora Tolerance Trials

Joe Ingerson-Mahar, PhD, Vegetable IPM Coordinator

  • Comparing the response of corn earworm to GMO and non-GMO sweet corn varieties and the resistance to BT corn

 

Diagnosing leaf diseases in sweet (and field) corn in the mid-Atlantic region

Dr. Alyssa Koehler, Field Crops Pathologist from the University of Delaware, recently posted a great diagnostic guide for important fungal leaf diseases in corn. Click here for more information. If you want to follow what is going on in Delaware you can sign up for their Weekly Crop Update by clicking here.