May 28, 2023

NYS IPM Field Crops Pest Report-May 28th, 2023

Black cutworm (Agrotis ipsilon)

Black cutworm moth captures have been very high in western and eastern NY this year. Larvae will likely be feeding soon. Watch for leaf feeding with the early larval instars. Once the larvae reach the 4th instar they will start cutting plants off. The threshold for black cutworm is 5% of the plants have been cut. Make sure to scout and have an educated decision behind the use of an insecticide.

black cutworm photo

black cutworm

Information on Black Cutworm

https://cals.cornell.edu/field-crops/corn/insects-corn/cutworms

 

True Armyworm (Mythimna unipuncta)

There have only been a few intense catches of true armyworm (see in the table below). While we have low populations this year there can be isolated cases that a field may get a higher population. It is best to scout every 7 to 10 days for all early season insect pests of corn.

The is damage by armyworm on corn plants in the 2nd leaf stage. They feed form the edge of the leaf into the midrid

True Armyworm Damage

Information on True Armyworm

https://cals.cornell.edu/field-crops/corn/insects-corn/armyworms

NYS Field Crops Pheromone Trap Data Report  Interactive Map

Black Cutworm Degree Day Accumulations

*Location for Intense Catches

Black Cutworm

Degree Days (Base 50)

Life Stage

Seneca Falls

Seneca County

April 20

 

153

1st-3rd Instar

Leaf Feeding

Amenia

Dutchess County

April 28

209

1st-3rd Instar

Leaf Feeding

Seneca Falls

Seneca County

April 26

132

1st-3rd Instar

Leaf Feeding

Amenia

Dutchess County

May 3

210

1st-3rd Instar

Leaf Feeding

Seneca Falls

Seneca County

May 3

132

1st-3rd Instar

Leaf Feeding

Linwood NY

Livingston County

May 4

142

1st-3rd Instar

Leaf Feeding

Amenia

Dutchess County

May 10

174

1st-3rd Instar

Leaf Feeding

Charleston

Montgomery County

May 23

37 Egg Laying

*Intense Catch is over 15 moths in a week.

True Armyworm Degree Day Accumulations

*Location for Intense Catches

True Armyworm

Degree Days (Base 50)

Life Stage

Phelps

Ontario County

April 20

 

153 Leaf Feeding

Phelps

Ontario County

April 30

132 Leaf Feeding

*Intense Catch is over 15 moths in a week.

 

 

 

Alfalfa Weevil (Hypera postica)

Alfalfa weevil may be an issue in alfalfa regrowth this year. It is important to keep scouting for alfalfa weevil over the next few weeks. Alfalfa weevil is normally controlled with the 1st cutting of alfalfa. Since it has been colder this year the weevil has been delayed and most areas are just starting to see damage. When scouting look for the holes in the leaves. The larvae feed on the buds before they unroll into leaflets. When they unroll it reveals the small holes in the leaflet. First instar larvae are very small and can be found in the buds of the alfalfa.

Alfalfa weevil shot holes

Alfalfa weevil shot holes

Alfalfa Weevil Damage-There are many shot holes in the leaves of the alfalfa

Alfalfa Weevil Damage

For more on alfalfa weevil please view the link to management information:

https://cals.cornell.edu/field-crops/forages/insects-forage-crops/alfalfa-weevil

 

Alfalfa Weevil Degree Day Accumulations from March 1 to May 28

Weather Station Location Alfalfa Weevil Degree Days Life Stage
Arkport 316 Leaf Feeding-1st instar
Bergan 323 Leaf Feeding-1st instar
Canton 297 Egg Laying
Ceres 293 Egg Laying
Conesus Lake 350 Leaf Feeding-1st instar
Corwin 299 Egg Laying
Geneva 325 Leaf Feeding-1st instar
Highland 515 Leaf Feeding-3rd  instar
Ithaca 351 Leaf Feeding-1st instar
Kinderhook 438 Leaf Feeding-2nd  instar
Lafayette 361 Leaf Feeding-1st instar
Laurens 293 Egg Laying
Northport 572 Leaf Feeding-4th  Instar
Peru 320 Leaf Feeding-1st instar
Red Hook 448 Leaf Feeding-2nd  instar
Versailles 353 Egg Laying
Watertown

260

 

Egg Laying

 

Alfalfa Weevil Life Stage Development

Growing Degree Days for peak (50%) occurrence of stage

Stage of Life Cycle Degree Days *
eggs hatch 280
Instar 1 315
Instar 2 395
Instar 3 470
Instar 4 550
Cocooning 600
Pupa 725
Adult Emergence 815

*48 degree F base temperature

 

Cereal Leaf Beetle (Oulema melanopus)

Cereal leaf beetles were out in force in western NY this week. Some wheat fields were sprayed this week for cereal leaf beetle. Make sure to use scouting and thresholds for making decisions for insecticide applications. Use the following lifecyle map to help make identification decisions and timing of scouting.

This is a graphic of the cycle of cereal leaf beetle. The adults are present from March to May. They start laying eggs in late April to May. Larvae are present from May through June. After that they pupate. Adults emerge in June to early July. In July the become dormant. They will overwinter as a adult.

Cereal Leaf Beetle Lifecycle

For more information on Cereal Leaf Beetle:

https://cals.cornell.edu/field-crops/small-grains/insects-small-grains