Agrotips for July 2010

Mulch to prevent blossom-end rot of tomatoes

If garden soils have adequate moisture and a pH in the range of 6.3 to 6.5, tomatoes are not likely to have blossom-end rot. Although this common problem is largely due to calcium deficiency, fertilization is not usually the answer. Any soil with a pH of 6.3 to 6.5 will contain enough calcium. However, during dry periods, plants cannot take up the calcium that is there. If your soil pH is good, you can optimize calcium availability by managing soil moisture. Make sure your plants get an inch of water each week, but be careful not to overwater. Apply 2 to 4 inches of mulch (pine bark, straw, leaf compost or other organic material) to help the soil retain moisture.

Got nematodes?

Fields with spotty, irregular patches of stunted, wilted, yellowing or dead plants are likely to have an infestation of plant-parasitic nematodes. The degree of injury to the roots varies with the age of the plant when attacked, and symptoms are most severe when feeding occurs during the first few weeks after planting. The only way to positively diagnose a nematode problem is to submit soil samples with roots for nematode assay. For best results, submit matching samples from a “bad” area and a nearby “good” area.

Collect cotton tissue samples.

Collect tissue samples (MRMLs + detached petioles) weekly beginning at early growth (at least by matchhead square or one week before first bloom) and continuing for three to four weeks after first bloom. Read about the new sampling protocol that NCDA&CS recommends at www.ncagr.gov/agronomi/pdffiles/09cotton.pdf.

Tissue Samplers . . . check out the Division’s new online help features.

The Agronomic Division has added three online instructional tools to help clients who submit tissue samples. These tools, in PowerPoint format, give precise instructions for collecting samples, filling out the sample information form and reading results on the plant report at www.ncagr.gov/agronomi/instruct.htm.

For more information, contact or visit the NCDA&CS Agronomic Division:
Physical Address -- 4300 Reedy Creek Road, Raleigh NC 27607-6465
Mailing Address -- 1040 Mail Service Center, Raleigh NC 27699-1040
Phone -- (919) 733-2655
Website -- www.ncagr.gov/agronomi.