Black cutworm 2014

Purdue specialists are recommending scouting fields continually for black cutworms. In years where planting is delayed, black cutworms seem to be more prevalent.

According to Christian Krupke, a Purdue entomologist, Indiana has some of the highest numbers of black cutworm moths ever recorded. Usually high trapped moth numbers coincide with increased egg laying. Black cutworm traps use a synthetic pheromone to gauge the year's prevalence of this pest. Even with the pheromone traps, it can be difficult to assess the level of damage that the cutworms are doing to a particular field.

So it's very important to walk your fields and look for black cutworm damage. When you see plants that have been clipped off it's too late to treat for Black cutworms. When scouting, look for small holes on the leaves. Small holes in the leaves indicate that the Black cutworms are still too small to do a lot of damage and it a good time to treat your fields.

Also, if you see damage you will want to look for the worm to make a positive identification. This pest will hang around the damaged plant and is usually just under the soil or debris near the plant.

Black cutworm moths are dark brown to black with dagger shaped makings on their wings. The larva vary from light gray to black and can be as small as 1/8 to as large as 2 inches long. These destructive pests like to overwinter in the southern states where the winter is milder, but migrate north when the weather starts to warm up.

There are several factors that affect whether or not black cutworms may be a problem in your fields. First, problems are less likely to occur in fall plowed fields. Second, in a late spring plowed field, problems are more likely. Third, corn following beans seems to be a factor in black cutworm infestations. Fourth, late planted fields can be a contributing factor to a black cutworm problem. Finally, minimally tilled fields are also an issue in black cutworm prevalence.

The general life cycle is that early in April the black cutworm moths arrive from the southern states where they have been overwintering. Then they start laying eggs till about mid-May. The larvae stage of the black cutworm can last till early April until they pupate in mid-June. They do the most damage to corn from late April to mid-June when the larvae stage is active. The second generation of adults begins their life cycle in mid-June, starting to pupate in mid-August. A possible third generation starts mid-September. The second and third generations don't seem to have the same damaging effects on corn as the first generation.

Back Cutworm damage should be scouted for by walking fields that have the factors mentioned above. The first signs of infestation usually appear in the weed portion of the field. These newly hatched larvae can leave small irregular holes in the leaves. Larger larvae may notch the stems of seedlings below the soil surface causing the seedlings to die. Some cut worms cut entirely though the stem causing the plant to fall over. They usually feed at night or on overcast days.

Controlling black cutworms can be difficult. Treated seed doesn't help with black cutworm control. Control may be warranted when 3-5 % of the plant leaves show damage and 2 or more cutworms are found per 100 plants. For more information please go to http://extension.entm.purdue.edu/fieldcropsipm/insects/blackcutworms.php or contact Ann Delchambre at 765-653-8411 or email adelchambre@purdue.edu

Upcoming Events:

June 9 -- Youth Pork Quality Assurance program, Fairgrounds, 5:30 p.m.

June 9 -- Putnam 4-H Junior Leaders, Fairgrounds, 7 p.m.

June 11 -- Putnam 4-H Basket Workshop, Fairgrounds, 1-4 p.m.

June 11 -- Putnam 4-H Photography Workshop, Putnam County Museum, 7 p.m.

June 12 -- Exploring 4-H Orientation Meeting, Fairgrounds, 7 p.m.

June 17 -- Indiana Farm Management Tour, Spence and Dubois County

June 28 -- Master

Gardener Garden Tour -- Tickets available at the extension office 10 a.m.