Potential for armyworm problems this spring
Over the past few years we have been mentioning the benefit in reading newsletters from other states to allow us to foresee what might happen in Ohio. For the true armyworm, a pest of wheat and corn in the spring, it is especially helpful to read Kentucky’s newsletter because when they see large populations of adult in their traps, we often see the same thing a few weeks later in Ohio. This scenario was especially the case in 2008, the last large outbreak year.
Kentucky is reporting seeing adult moth captures this spring similar to outbreak years of 2006 and 2008 (see http://www.uky.edu/Ag/IPMPrinceton/counts/taw/tawgraph.htm). In their most recent newsletter from April 19, they are calling this to the attention of their growers. If their higher numbers continue, we would also expect a large flight of adult moths in the coming weeks into Ohio.
As pointed out in their article, this does not mean that any individual field will have an outbreak, let alone any area of Ohio. However, it will mean that Ohio growers should be attentive to potential problems in both wheat and corn, especially when the latter is adjacent to wheat or planted into a rye cover crop, a preferred egg laying site. See the fact sheet http://ohioline.osu.edu/ent-fact/pdf/0036.pdf for more information on this insect.
Other insects of concern at this time include:
Ÿ Alfalfa Weevil: Growers should continue to watch for weevil feeding in their alfalfa fields, especially in southern and central Ohio. Feeding in northern locations will probably not have started yet, although it will begin shortly.
Ÿ Cereal Leaf Beetle: We are beginning to see adult cereal leaf beetles along with eggs on wheat plants. As wheat continues to grow and flag leaves emerge, and as spring-planted oats begin their growth, growers should keep an eye out for the presence of cereal leaf beetle larval feeding. A big change this year with this pest is that we are reducing the threshold to one larva per stem or flag leaf. Our colleagues on the East Coast have done research suggesting that the thresholds that were being used were too high. Thus, based on their research, we are dropping our thresholds in Ohio down to a single larva per flag leaf. See the fact sheet http://ohioline.osu.edu/ent-fact/pdf/0038.pdf for more information on the cereal leaf beetle.
Ÿ Black Cutworm: From reading newsletters from neighboring states and examining our own traps, it is obvious that black cutworm adults are now flying in the Midwest. Black cutworms will begin cutting corn in May, especially in corn planted into weedy fields, with chickweed being a preferred weed species. Of extra concern this coming spring is that much of the corn will be relatively small or just emerging when cutworm larvae become active. A fact sheet on black cutworm is at http://ohioline.osu.edu/ent-fact/pdf/0035.pdf.
Ÿ Slugs: We have been getting reports of slug eggs being found in numerous fields in Ohio, and expect egg hatch to begin soon in Ohio starting with the southern locations moving northwards. For no-till growers or others that have had problems with slugs in previous years, they will need to begin to be watching for signs of slug feeding on emerging crops. Because many fields will be planted relatively late because of the wet conditions, the conditions exist for significant problems if a field has a large populations of slugs. For information on slugs, see http://ohioline.osu.edu/ent-fact/pdf/0020.pdf on the Agronomic Crops Insects web page. In terms of molluscicides, the two metaldehyde materials, Deadline MPs and Orcal Snail and Slug bait, and an iron phosphate bait known as Sluggo, are available. The most important thing for good slug control is even coverage with the bait when broadcasting.
Kentucky is reporting seeing adult moth captures this spring similar to outbreak years of 2006 and 2008 (see http://www.uky.edu/Ag/IPMPrinceton/counts/taw/tawgraph.htm). In their most recent newsletter from April 19, they are calling this to the attention of their growers. If their higher numbers continue, we would also expect a large flight of adult moths in the coming weeks into Ohio.
As pointed out in their article, this does not mean that any individual field will have an outbreak, let alone any area of Ohio. However, it will mean that Ohio growers should be attentive to potential problems in both wheat and corn, especially when the latter is adjacent to wheat or planted into a rye cover crop, a preferred egg laying site. See the fact sheet http://ohioline.osu.edu/ent-fact/pdf/0036.pdf for more information on this insect.
Other insects of concern at this time include:
Ÿ Alfalfa Weevil: Growers should continue to watch for weevil feeding in their alfalfa fields, especially in southern and central Ohio. Feeding in northern locations will probably not have started yet, although it will begin shortly.
Ÿ Cereal Leaf Beetle: We are beginning to see adult cereal leaf beetles along with eggs on wheat plants. As wheat continues to grow and flag leaves emerge, and as spring-planted oats begin their growth, growers should keep an eye out for the presence of cereal leaf beetle larval feeding. A big change this year with this pest is that we are reducing the threshold to one larva per stem or flag leaf. Our colleagues on the East Coast have done research suggesting that the thresholds that were being used were too high. Thus, based on their research, we are dropping our thresholds in Ohio down to a single larva per flag leaf. See the fact sheet http://ohioline.osu.edu/ent-fact/pdf/0038.pdf for more information on the cereal leaf beetle.
Ÿ Black Cutworm: From reading newsletters from neighboring states and examining our own traps, it is obvious that black cutworm adults are now flying in the Midwest. Black cutworms will begin cutting corn in May, especially in corn planted into weedy fields, with chickweed being a preferred weed species. Of extra concern this coming spring is that much of the corn will be relatively small or just emerging when cutworm larvae become active. A fact sheet on black cutworm is at http://ohioline.osu.edu/ent-fact/pdf/0035.pdf.
Ÿ Slugs: We have been getting reports of slug eggs being found in numerous fields in Ohio, and expect egg hatch to begin soon in Ohio starting with the southern locations moving northwards. For no-till growers or others that have had problems with slugs in previous years, they will need to begin to be watching for signs of slug feeding on emerging crops. Because many fields will be planted relatively late because of the wet conditions, the conditions exist for significant problems if a field has a large populations of slugs. For information on slugs, see http://ohioline.osu.edu/ent-fact/pdf/0020.pdf on the Agronomic Crops Insects web page. In terms of molluscicides, the two metaldehyde materials, Deadline MPs and Orcal Snail and Slug bait, and an iron phosphate bait known as Sluggo, are available. The most important thing for good slug control is even coverage with the bait when broadcasting.
Published: May 4, 2011
