A popular Purdue University agronomic reference book is flying off the shelves this winter, but farmers who act quickly still can ensure a copy lands in their mailboxes.

Sales of the 18th annual "Corn and Soybean Field Guide" are up from 2005, said Corey Gerber, director of Purdue's Crop Diagnostic Training and Research Center and field guide project coordinator.

"Already this year we've sold 20,000 books, which leaves us with about 1,000 books at Purdue's Media Distribution Center," Gerber said.

The little yellow book, commonly called the "pocket guide," provides a wealth of management advice and information on raising corn and soybeans. The nearly full-color guide is 293 pages.

"This year we've expanded the number of pages by about 50," Gerber said. "The primary changes have been in the corn and soybean production sections. Bob Nielsen and Shawn Conley, Purdue Extension's corn and soybean specialists, provided quite a few photos that focus on the growth and development stages of corn and soybean plants. The photos range from when plants are emerging from the ground through the reproductive stages."

Crop diseases also receive special treatment in this year's field guide.

"We upgraded the soybean disease section this year," Gerber said. "One of the diseases added to the book was soybean rust. Specifically, the information that we added was how to identify rust, how to submit leaf samples to Purdue's Plant and Pest Diagnostic Laboratory for analysis and fungicides labeled for rust. Other diseases added to the soybean disease section were frogeye leaf spot, bacterial pustule and downy mildew."

Other corn and soybean topics covered in the book include:

• Identifying and controlling crop insects.
• Maintaining proper soil fertility and diagnosing nutrient deficiency.
• Recognizing common broadleaf and grass weed seedlings.
• Diagnosing soil compaction and managing crop residue.
• Making delayed planting and replanting decisions.
• Selecting corn hybrids and soybean maturity groups.
• Identifying herbicide injury.

The field guide also contains numerous herbicide, insecticide, fungicide and fertilizer tables.

Sixteen Purdue Extension specialists representing the agronomy, botany and plant pathology, and entomology departments contributed content and/or photos for the field guide. The U.S. Department of Agriculture's Wildlife Services also contributed material.

The field guide is $6 and is available by calling the toll-free Purdue Extension hotline at (888) 398-4636 (EXT-INFO) and asking for the Media Distribution Center. The publication code for the field guide is ID-179.

A form for mail orders can be downloaded online. The Web page also contains a link for viewing sample pages from the 2006 field guide.

Orders also can be placed online at the Purdue Extension Education Store Web site.