August 25, 2008

Janet Knodel

Extension Entomologist

janet.knodel@ndsu.edu

The best time to treat is when more than half of the plants in a field are beginning to show yellow ray petals (R5.1) to 30% of the head shedding pollen (R5.3) and the rest of the plants in the field are still in the late bud stage (R4). Although insecticides applied to sunflower at the bud stage will kill seed weevils, treatments at that stage are not economical or effective because (1) seeds have not developed to a stage suitable for oviposition, (2) eggs within the weevil are not mature, and (3) adult weevil emergence is still continuing. If spraying is done too early, weevils can re-infest a field requiring a second treatment. At R5.1, the young larvae of banded sunflower moth are typically beginning to feed on the disk flowers, are exposed on the head and are susceptible to the insecticide treatment. Application at an earlier growth stage may be warranted if monitoring reveals earlier than normal egglaying activity for banded sunflower moth. Banded sunflower moth and red sunflower seed weevil can both be controlled with a well-timed spray, usually near 10% of the head shedding pollen or R5.1 in oilseed sunflowers. Confection sunflowers usually require two insecticide applications to control sunflower head insects: one near R5.1 and another one week later due to the industry standards for very low insect damage. Sunflower fields should always be scouted for both insect pests through R5.7.

Joel Ransom

Extension Agronomist for Cereal Crops

joel.ransom@ndsu.edu

In the parts of the state that were not ravaged by drought, winter wheat yields were good again this season. If you are planning on planting winter wheat this fall, the following are a few suggestions:

Planting date: The optimum planting date for the northern half of the state is September 1-15 and for the southern half September 15-30. The last date that winter wheat can be planted will depend on the weather. The seed must germinate in the fall so that the crop will be vernalized in the spring. A larger plant will over winter better than a seedling or a sprouted seed.

Planting depth: Adequate moisture for establishing winter wheat is often a concern as the soil profile is usually depleted of moisture in the fall. If there is little or no moisture in the soils surface, planting shallow (1 to 1.5 inches deep) and waiting for rain is recommended.

Seeding rates: Generally a seeding rate of 900,000 to 1 million viable seed per acre is adequate. Higher seeding rates may be appropriate if planting late or when planting into poor seedbeds.

Plant in to crop residue: The best winter survival is achieved when winter wheat is no-till planted into standing crop residues that are able to catch and retain snow. Planting winter wheat into a low residue crop such as soybean increases the risk of winter kill, so only the most winter hardy varieties should be grown (see data on winter survival in 2005/06 in the following table and at www.ag.ndsu.nodak.edu/aginfo/smgrains/WWsurvial.htm.

Variety selection: In addition to agronomic characteristics such as plant height, yield, and disease and lodging resistance, also carefully consider the winter hardiness of a variety. In many years there is a direct correlation between winter survival and yield. Yield data from the 2008 season are being posted on the Small Grains Page

http://www.ag.ndsu.edu/smgrains/. Data from previous years’ trials are available at http://www.ag.ndsu.edu/variety/index.htm. . Sources of certified winter wheat seed are ND State Seed Department or at the Small Grains Page.