CropTech: Weeds Like It Hot

January 5, 2011 10:16 AM

Weeds Like it Hot

Add weeds to the dire predictions that come with climate change. As temperature and carbon dioxide levels in the atmosphere change, so will wily weeds.

Lewis Ziska, a Beltsville, Md., based USDA-Agricultural Research Service specialist in crop systems and global change, told growers at the recent Illinois AGMasters Conference to prepare to see things pop up on their farms that they’ve never seen before.

Rising temperatures will also expand weeds into higher latitudes or higher altitudes. For example, Ziska says itchgrass, a profusely tillering, robust grass weed, could invade the central Midwest and California with only a 3° warming trend. Ziska is studying how invasive and noxious weed species, such as kudzu and Canada thistle, might alter under changing conditions.

There are 45 major crops in the U.S. and 410 weed species associated with yield reductions for those crops. Ziska notes that weeds have a greater genetic diversity than crops. Consequently, if a resource such as light, water, nutrients or carbon dioxide changes within the environment, it’s more likely that weeds will show greater growth and reproductive response.

Syngenta Turns Over a New Leaf

Soybean growers who prefer to buy seed from regional suppliers will benefit from Syngenta’s announcement that it is beginning to outlicense soybean germplasm.

It’s one of several moves the company is making after assuming full ownership of GreenLeaf Genetics LLC. The transaction dissolves an outlicensing joint venture between Syngenta Seeds Inc. and DuPont business Pioneer Hi-Bred that has been operating since 2006.

Todd Martin, head of Syngenta independent business, says the joint relationship was successful, but the market landscape has changed. "As a single owner, we will be able to move more quickly in broadening access to our rapidly expanding portfolio of innovative traits and germplasm," Martin says.

The varieties initially offered will combine elite Syngenta soybean genetics with Monsanto Company’s Genuity Roundup Ready 2 Yield trait. Independent seed companies will be able to plant these initial varieties for testing and production this year.

Pioneer and Syngenta quickly demonstrated they will continue to work together. As of Jan. 1, Pioneer has a non-exclusive, global license to Syngenta’s corn rootworm trait Agrisure RW. The license gives Pioneer full stacking rights of the trait that provides protection from below-ground coleopteran insects.

Figure that Refuge

The right plan for refuge compliance is as close as your computer. The National Corn Growers Association (NCGA) joined forces with agribusiness to come up with an easy-to-use, downloadable calculator representing the latest products on the market.

The thing to remember this year is that despite all the talk about refuges incorporated in a single bag, those products are at least a year away. Pioneer Hi-Bred’s Optimum Acre Max 1 does integrate the rootworm component, but there remains a 20% separate European corn borer refuge. Amount of refuge acreage and proximity to field vary by technology.

The new NCGA tool includes all commercial Bt products on the market and features a trait selection process that allows farmers to run several planting scenarios on a field-by-field basis. Its updated interface and clearer planting options makes refuge calculation simpler. To download the calculator, visit

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