As of Tuesday, Nov. 4, the drought monitor report indicates essentially no change from last week. The six-to ten-day outlook (Nov. 11 to 15) indicates a 50 to 70% chance of above normal temperatures and a 40 to 50% chance of leaning below normal precipitation. The eight to 14-day outlook (Nov. 13 to 19) indicates a 60 to 70% chance of leaning above normal for temperatures and 33 to 40% chance of leaning above normal for precipitation.
So far, we have discussed how to implement Integrated Pest Management for weeds and insects. How a variety of practices a producer can use to minimize the use of pesticides: cultural practices, sanitation, crop breeding, etc. As we briefly discuss IPM and diseases, a producer has more options before implementing chemical control. Keep in mind that plant disease are divided into two categories, abiotic and biotic. Abiotic diseases include nutrient deficiencies, heat, drought, and other similar events. Biotic factors include fungi, bacteria, viruses, and nematodes. We are focused on biotic diseases today and in plants.
• Before discussing nonchemical approaches, it helps to understand what chemical control is available. Just as with people, there aren’t many, if any options for viral control. Once infected, it’s too late. There are bactericides for certain plant diseases which would be used on above ground plant parts. There are many fungicides. Some are systemic, meaning the are absorbed into the plant, move to the infected site and control, or they act to prevent infection. Seed applications are common as are applications to above ground plant parts. Protectants serve as a physical barrier and must be applied prior to infection. Rainfall or irrigation would cause a reapplication. Some formulations are a combination of a systemic and protectant. And with multiple applications, it is recommended to change up modes of action to prevent resistance.
• Here, crop rotation for disease residing in the soil or crop residue are quite effective and the more dissimilar and longer the rotation, the better. Along with this using disease-free seed and overall sanitation protocols also help as does eliminating alternative hosts such as many weeds. Improving drainage in poorly drained areas helps relieve root rots and seedling blight. Managing stresses such as fertility also help plants to be more resistant to biotic diseases. Manipulating planting dates to avoid for example cold soil conditions helps.
• Either through conventional breeding or genetic engineering, breeding for resistance or tolerance are a major, fairly long lasting, and cost-effective way to eliminate economically damaging disease pressure. However, it is common for resistance to break down over time so there must be continuous research. The development of SCN soybeans where soybean cyst nematode is a problem or breeding for resistance to rust species in wheat.
• Whiles there’s more, a really significant key is eliminating vectors, how the disease arrives at the plant. This is often an insect or mite, say the wheat curl mite and many aphid species. Primarily piercing-sucking insects and by eliminating alternate hosts from the area.
Dr. Victor L. Martin is the agriculture instructor/coordinator for Barton Community College. He can be reached at 620-792-9207, ext. 207, or martinv@bartonccc.edu.
