2001-2002 Herbicide Management Chart

Testing Notes:
Ratings presented are derived from the analysis of one to three years of greenhouse screening trials conducted from 1996-98. These trials compared % visual injury, seedling weight and seedling height versus untreated controls of each hybrid. Additionally, one to three years of field screening was conducted using a rating system combining % of injured plants with severity of injury.
Note: Greenhouse results are from controlled environments and may or may not accurately reflect field results where temperature, humidity, soil type and soil pH are variable

Amide tested was Harness or Surpass, this family includes Axiom�, Dual II�, Frontier�, Lasso�, Topnotch� plus other premixes.

IMI (Imidazolinone) Half rates of Pursuit and Raptor were used to simulate imidazolinone carryover injury. This family includes Lightning�, Pursuit Plus and other premixes. Carryover risk increases following seasons with lower than normal rainfall, as well as in soils with high clay or organic matter content.

Pigment Inhibitor tested was Balance. This specific herbicide prevents the synthesis of a photosynthetic pigment.

Pigment Inhibitor II tested was Callisto. Like Balance this specific herbicide prevents the synthesis of a photosynthetic pigment, however the enzyme that is blocked by Callisto is different than the enzyme blocked by Balance.

SU (Sulfonylureas) This family of herbicides has many members and screening trials have been done with Accent, Basis Gold�, Beacon�, Exceed�, Permit�, and Spirit�. Our rating is based on the individual hybrid's general response to the range of SU�s tested. Only Accent was screened in 2001 trials.

Sulfonanilides tested were Python and Hornet, this family includes Scorpion III and other premixes.

Growth Regulators tested were Clarity and 2,4-D Amine, this family includes Banvel�, Stinger*, Distinct�, and other premixes.

Dinitroaniline tested was Prowl, this family includes Sonalan*, Treflan and other premixes.

Buctril �burn� is most likely to occur when higher-than-labeled rates are applied.

SU (Sulfonylureas) This family of herbicides has many members and screening trials have been done with Accent, Basis Gold, Beacon, Exceed, Permit and Spirit. Our rating is based on the individual hybrid's general response to the range of SU�s tested. Only Accent was screened in 2001 trials.

Herbicide Management Recommendations

Amides (Chloroacetamides)
Injury is more common on sandy soils with low organic matter. Cool, wet conditions, soil crusting and deep planting depths may also increase the potential for injury. For hybrids we have rated �Carefully Manage� we offer the following suggestions.

1. Avoid using on sandy, low organic matter soils.
2. Avoid planting corn too deep.
3. Choose a chloroacetamide herbicide that contains a safener.
4. If crusting occurs, a properly operated rotary hoe can assist emergence.
5. Avoid extremely early planting dates that may slow emergence from cold soils.

Imidazolinone Carryover
Carryover injury can occur following soybeans treated with imidazolinone herbicides or on non-Clearfield� corn following a Clearfield corn crop treated with Lightning. Imidazolinone carryover is most likely to occur following a season of lower than normal rainfall, as well as in soils with high clay or organic matter content. Also, acid soils with a pH level of 5.5 or less have increased potential for carryover.

1. Consider the use of Clearfield hybrids following imidazolinone treated crops, particularly after a dry season or late season imidazolinone applications, or on soils with a pH of 5.5 or lower.
2. Avoid overlapping applications when spraying imidazolinone herbicides.

Pigment Inhibitor (Balance) and Pigment Inhibitor II (Callisto)
Injury from pigment inhibitors is more likely on sandy soils with low organic matter. Cool, wet environmental conditions may also increase the risk of crop injury. For hybrids we have rated �Carefully Manage� we offer the following suggestions.

1. Avoid using on sandy, low organic matter soils.
2. Avoid shallow planting (1.75� minimum depth) and make sure the seed furrow is properly closed. .
3. Avoid extremely early planting dates that may slow emergence from cold soils. .
4. Comply with labeled rate recommendations given for specific soil types. .
5. If crusting occurs, a properly operated rotary hoe can assist emergence. .

SU�s (Sulfonylureas)
Injury from sulfonylureas is more likely when application occurs after the plants are 10-12 inches tall or when there is stress from cool/dry growing conditions. For hybrids we have rated �Carefully Manage� we offer the following suggestions.

1. Make applications early within the time frame specified by the herbicide label.
2. Have spray applications completed before the hybrid is 10-12 inches tall.
3. Avoid applying when the corn in under stress, particularly cool, dry growing conditions.
4. Consult label before applying sulfonylurea herbicides to hybrids less than 88 day relative maturity.

Sulfonanilides
Injury is more likely to occur when excessive rainfall leads to extended cool, wet conditions following soil application of Hornet*. For hybrids we have rated �Carefully Manage� we offer the following suggestions.

1. Avoid applying when air temperatures are near freezing or when extended cool, wet soil conditions are forecast.
2. Avoid post-applying to corn that is under stress from cold weather, hot weather (>90?F),drought, or when soils are saturated.
3. Do not use Counter� or Thimet� insecticides.
4. Avoid applications to soils where the pH is 7.8 or greater.

Growth Regulators
Injury from growth regulators most often occurs when a hybrid is under stress or the herbicide is applied at or beyond the suggested stage of growth, or when high winds follow within a few days after the herbicide is applied. For hybrids we have rated �Carefully Manage� we offer the following suggestions.

1. Avoid applying when daytime temperature are high and the corn plants are growing very rapidly.
2. Make applications early within the time frame specified by the herbicide label.
3. Avoid or delay application when environmental conditions such as cold soils, drought or high winds may cause excessive stress. (Brittleness associated with growth regulators may leave some hybrids sensitive to green snap).
4. Read label carefully reviewing rate recommendations for specific stages of growth.

Dinitroanilines (Prowl)
Injury most often occurs in areas of a field with light-textured soils and in areas where overlaps of application occur such as end rows and point rows.

1. Avoid overlapping of herbicide applications.
2. Use appropriate rates for light-textured soils.
3. If injury occurs it may be helpful to throw soil up around the base of plants to foster brace root development.

Buctril
Injury is most likely to occur when applying higher than labeled rates to corn before the proper growth stage or when spray applications are overlapped. Additionally, some environmental conditions may lead to a thinning of the leaf cuticle and plants will absorb more than a normal amount of herbicide and cause leaf burn symptoms.

1. Avoid overlapping of herbicide applications.
2. Avoid postemergence applications prior to the 4th leaf stage
3. Avoid application shortly after conditions change from cool weather to high soil moisture, high humidity and high temperatures, conditions that lead to the thinning of the leaf cuticle.