METHYL BROMIDE VS. TELONE II:

This table answers some of the most frequently asked questions about the comparative effectiveness of methyl bromide and Telone II. The greater cost of methyl bromide can be offset by its broader spectrum of activity (which may or may not be needed in a particular situation), shorter waiting periods specified on labels (days versus weeks), greater depth of penetration and somewhat greater ability to move through cooler, wetter soils as indicated by the preceding tables.

Both fumigants have traditionally been applied via knife like fumigation shanks pulled behind a tractor. Different shank spacings and depths of injection are chosen for different crops and soils. In general, shank spacings indicated in University of California publications are closer than those used by commercial applicators. Traditionally, because of its greater volatility methyl bromide was covered with a polyethylene tarp to slow down the rate at which the fumigant left the soil, thus providing control in the top few inches of soil. Following application of Telone II, the soil surface was typically "sealed" by a ring roller drug behind the fumigation rig. In more recent times, methyl bromide has been utilized without a tarp which lessens the cost of the application but also decreases effectiveness in the top few inches of soil. With the reinstatment of use of Telone II following several years of suspension of use, new application equipment and sealing techniques have come into use.

Land preparation is an important aspect for successful use of nematicides and is similar for both fumigants.

Nematicides do not typically erradicate nematodes. When used properly, they can reduce nematode popoulations below detectable levels allowing a crop to be planted and a healthy root system to develop before populations increase once again to damaging levels.

Fumigants can also reduce levels of beneficial bacteria. This can slow the rate of decomposition in soils and in some cases result in unexpected phytotoxicity until normal levels are reestablished.

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