IPM Notes from August 8, 2014

The walk began with a brief talk about the spittlebug, and what it leaves on the plant. It can suck juices from a plant, like alfalfa, and through its saliva process, leaves a small gooey substance on the plant.

Shortly after the IPM crop scout tour on August 7th, the harvested sweet corn was plowed under to prevent disease and possible insect damage. The open field will soon be seeded with a cover crop to prevent erosion.

The field corn is in the late dough stage, near the dent stage. The kernel substance is more starchy, but still milky. Most of the husks have open ears where moisture can enter, along with sap beetles. More importantly, the open ears can lead to disease such as micotoxins. Preferably one would want a tighter husk.

Regarding the field corn, an estimated 206 bushels per acre is expected to be harvested in late September or early October. This was calculated by taking several samples of 25 to 26 ears per 17.5 feet, then taking a representative sample of 5 ears and counting the kernels (length & width) of each. The average number of kernels (716) on each of the 5 ears times the average number of ears 25.5 (within 17.5 feet) equaled 18,258 kernels. This total (18,258) divided by 80 gave 228 bushels per acre on a normal basis. Allow for 10 percent imperfections equals 206 bushels per acre.

The popcorn is in the pollination stage having tassels and silks. There is some rust appearing on the plant, but for the most part the popcorn plant looks very good. The popcorn will be of the red and yellow variety.

Some of the lower layer of leaves on the soybean plant shows septoria leaf spot because the plants are quite tall from the rain. There is some beetle damage showing on the leaves. Also noticed were the brown stink bug and green clover worm. Stinkbugs can be an issue because they pierce the pod, suck the juices, and there is loss of pods.

In the demonstration plots the pepper plants look healthier with some added fertilizer. . The garden-in-a-bag plants have been doing better with water and fertilization. The strawberry plants were sprayed again for powdery mildew. They have been sprayed over the past month For the first year they look good.

Below are the summaries for the insects caught in the three insect traps.

• Trap 1 (Black Cutworm) – 12 fall armyworm, 1 chafer beetle..
• Trap 2 (Fall Armyworm) –3 fall armyworm, 3 honey bee, 2 bumble bee.
• Trap 3 (European Corn Borer) – 1 bumble bee, 1 noctuid.

Pest of the Week - Fall Panicum

A native of North America, fall panicum flourishes throughout the United States except in some areas of the north central and northwestern states. It has been blamed for causing nitrate poisoning and extreme sensitivity to light in livestock. This latter condition, called "photosensitivity," results in severe burning and peeling of any skin that is not protected from the sun.

Stem and leaf-base characteristics of a typical grass.
Ontario - Ministry of Agriculture

Fall panicum (Panicum dichotomiflorum) has a zigzag appearance as the buds turn out at the nodes. The zigzag growth pattern is one of the primary identifying characteristics.  It has a very rounded stem, grows to 7’ and there is a purple tinge to its inflorescence.

Fall panicum. A. Plant. B. Leaf-base. C. Panicle. D. 2 spikelets.
Ontario - Ministry of Agriculture

Strand Memorial Herbarium

Panicle, the name for the type of seed head produced by this grass, gives fall panicum both its common and scientific names. Because its seeds do not mature until late summer or autumn, the grass is commonly called fall panicum. Dichotomiflorum is a Latin word that refers to a distinguishing feature of fall panicum: the individual flowers (florets) are arranged in pairs.

Other common names for fall panicum include fall panicgrass, spreading witchgrass, spreading panicgrass, spreading panicum, sprouting crabgrass, and kneegrass. The last name is an apt description of the nodes, which are swollen, slightly bent, and very shiny.

Sometimes fall panicum is mistaken for johnsongrass (Sorghum halepense) or barnyardgrass (Echinochloa crus-galli). However, johnsongrass has a membranous ligule unlike that of fall panicum and johnson grass seedlings also do not have hairs on the lower leaf surface like those of fall panicum. Barnyardgrass does not have a ligule at all and barnyardgrass seedlings might only have hairs near the leaf base.

Additional Information

Fall Panicum - Penn State University

Panicum Images - Strand Memorial Herbarium

Identifying Grass Seedlings - IPM University of Missouri

Botanical Dictionary - University of North Carolina - Chapel Hill

IPM Notes from July 31, 2014

The trial sweet corn was harvested by Master Gardeners last Monday and Wednesday for a total of 2,200 and 1,900 pounds respectively. More of the corn will be picked Friday. Before the corn was harvested, various measurements of the 20 different varieties (20 rows) were taken on such things as stalk height, ear height, number of suckers, corn length and number of husks open. Normally the corn is cut-down soon after harvesting, preventing further disease. This corn was donated to Farmers Against Hunger.

The field corn is in the early doe stage. The kernel substance is between starch and milky. Although some of the kernels didn't fill the entire husk, and one appeared slightly curved, for the most part the corn shows good earfuls. They are expected to be harvested late September or early October.

The popcorn likes the hotter weather, but not over 85 degrees. It does not prefer the cooler nights that we've been experiencing lately. Since it is the latest cornfield to be seeded, it may be a buffet for insect and deer damage. The popcorn will be of the red and yellow variety.

Some of the lower layer of leaves on the soybean plant shows septoria leaf spot. The taller plants are showing signs of soybean aphids. Soybeans can take about 60-70% defoliation and still produce a crop that can be harvested.

The other soybean field with younger (and smaller) plants is now in the 3rd and 4th trifoliate leaf stage. The plants are outgrowing the signs of spotting, and also curling from thrip damage that was mentioned last week. Since this field was a no-till field, insect damage and disease (fusarium and septoria) early on seemed more prevalent.

In the demonstration plots the pepper plants, with some added fertilizer have bounced back. The garden-in-a-bag plants have been doing better with water and fertilization. The strawberry plants were sprayed again for powdery mildew. For the first year they look good.

Below are the summaries for the insects caught in the three insect traps.

• Trap 1 (Black Cut Worm) – 3 Japanese beetles, 2 black cut worms, 1 each of chafer beetle, click bug, sap beetle and noctuid.
• Trap 2 (Fall Armyworm) –2 Fall armyworm, 1 each of chafer beetle and wasp.
• Trap 3 (European Corn Borer) – 2 Bumble bees, 1 each of lightning bug and stink bug.