Wheat leaf rust was observed on April 9 near Hutchinson. This is the first report of leaf rust in central Kansas for 2010. The disease was found in research plots intended for variety screening and a variety performance test. The leaf rust is still limited to the lower canopy, and the incidence and severity of the disease remains low (less than 2 percent). The varieties affected include Overley and Lakin.
Lakin is an older variety now used mostly for research purposes, but Overley still holds considerable acreage in the state. Both varieties are known to be susceptible to leaf rust. Moderate levels of powdery mildew were observed in multiple varieties.
Bob Hunger, Oklahoma State University, is reporting that the stripe rust he observed on Jagalene previously is still active. Jagalene should be resistant to stripe rust and this report is cause for concern. To date, no stripe rust has been found in Kansas.
Weather conditions in early April have not been conducive for the continued spread of the disease with temperatures in the 80s and lack of rainfall in most areas. But this week the cool temps and humid conditions could change the rust outlook in a hurry. The crop is still at or near the jointing stages of growth in many fields. Most agronomists suggest that the crop is behind in growth and development, although the warm temperatures may "push" the crop ahead. This delay in crop development is a double-edge sword. The delay provides time for producers to evaluate and respond to emerging disease threats but also means that the crop may experience severe disease during the early stages of grain fill when it is most vulnerable to yield loss. Research indicates that the most effective time to apply a foliar fungicide is between flag leaf emergence and heading. We continue to see warning signs of leaf rust and stripe rust that suggest we have at least a moderate risk of disease-related yield loss in Kansas. Growers should continue to monitor the disease situation in their region and prepare to make fungicide applications if warranted.
The above information was provided by Erick De Wolf, Kansas State Extension plant pathologist.
Here are some important reminders to consider:
* Wheat varieties susceptible to multiple foliar diseases are most likely to give a desirable yield response. Typical yield response for a susceptible variety ranges between 3 and 14 percent with an average response of 10 percent.
* Fields with a yield potential of 40 bu/a are reasonable candidates for fungicide application. Seed production fields are a top priority.
* Fungicide costs vary between $4 and $20 per acre with Folicur and generic forms of tebuconazole being the least expensive.
* A comparison of product efficacy is provided in the K-State publication Foliar Fungicide Efficacy Ratings for Wheat Disease Management, 2010. (EP130), www.ksre.ksu.edu/library/plant2/EP130.pdf.
Setting out tomatoes
Gardeners often try to get a jump on the season by planting tomatoes as early as possible. Though this can be successful, there are certain precautions that should be observed.
* Harden off plants: Plants moved directly from a warm, moist greenhouse to the more exposed and cooler conditions outside may undergo transplant shock. Transplant shock causes plants to stop growing for a time. Plants can be acclimated to outside conditions by placing them outdoors in a location protected from wind and full sunlight for a few days before transplanting. Another way to harden off plants is to transplant them and place a cardboard tent or wooden shingle to protect them from wind and sun for two to three days. The best conditions for transplanting is an overcast, still day.
* Protection from frost: Tomatoes cannot tolerate frost. Though we are past the average date of the last frost in most of Kansas, watch the weather and cover the plants if frost threatens. A floating row cover or light sheets can be used for protection. Actually, a floating row cover can be left on the plants for two to three weeks to increase the rate of growth and establishment.
* Adequate soil temperature: Tomato roots do not do well until soil temperatures reach a fairly consistent 55 degrees. Check the temperature at two inches deep during the late morning to get a good average temperature for the day. Plastic mulch can be used to warm soil more quickly than bare ground. Purple leaves are a sign of phosphorus deficiency due to too-cool soils.
* Other tips for getting tomato plants off to a fast start include:
1) Use small, stocky, dark green plants rather than tall, spindly ones. Smaller plants form roots rapidly and become established more quickly than those that are overgrown.
2) Though tomatoes can be planted slightly deeper than the cell-pack, do not bury plant deeply or lay the stem sideways. Though roots will form on the stems of tomatoes, this requires energy that would be better used for establishment and growth.
3) Use a transplant solution (starter solution) when transplanting to make sure roots are moist and nutrients are readily available.
4) Do not mulch until the plant is growing well. Mulching too early prevents soil from warming up.
Setting out peppers
Although many of us may want to plant some of the numerous types and varieties of peppers (hot and sweet) about the same time as tomatoes, that's not always the best advice. You see, peppers like the soil temperatures about 10 degrees warmer than the tomatoes. If you wait until about May 10 through 15 to set out tomatoes, then that would be ideal for peppers also. Many of the tips covered with tomatoes are also true for peppers, except the soil temperature.
University and industry research studies clearly show that waiting until the soil has warmed up will give far superior yields and plant growth rather than trying all the neat tricks commonly used when planting early tomatoes.
For our area, waiting one to two weeks after the early tomato plants were set out (last of April) will give the peppers the warm soil temps that they so desire. You see, air temperature (frost) is always the critical factor for many of our early garden plants, but the pepper roots really thrive in the warmer soils. When planted in cool/cold soils, they tend to just "live," but actual root and top growth will wait for the right temps. Research has shown the early yields and total yields for the season will be much greater when the pepper plants start off with ideal growing conditions. The cool soil and air temps tend to stunt the plants.
As with tomatoes, the best choice for mulching peppers is to wait until roots have grown deep (around the time of flowering) then mulch plants with a heavy layer (three to four inches) of organic mulch. This delay allows time for the soil to warm considerably, and the plants to establish deep roots. Mulch helps retain soil moisture, prevent some soil-borne diseases and reduce or eliminate weeds. Organic mulches cool soil surface and black or red plastic mulches warm soil surface. Typical organic mulches include layered newspaper covered with straw or hay, grass clippings (as long as no weed-killers are used) and shredded or chipped wood mulches.
For more information or assistance on this or other topics, please call the Extension Office at 272-3670, located at 501 S. Ninth St.