Granite GR herbicide is a postflood, postemergence herbicide for selective control of susceptible grass, broadleaf, and sedge weeds in California rice. Susceptible weeds at the 1 to 3 leaf stage emerged at the time of application will be controlled. Apply Granite GR directly into flooded fields when rice is at a minimum 2 1/2 leaf stage of growth. At this stage, the second leaf is fully expanded or unfurled with the third leaf emerged but not expanded. Average water depth at application should be maintained at 4 to 5 inches, with a minimum water depth of 3 inches in the shallowest part of the field with completely submerged weeds and no exposed soil.
Rice crops grown under adverse environmental conditions, such as extreme cold or heat, may express temporary crop injury when Granite GR is applied including slight height reduction or root stunting. Any crop stress or environmental factors which decrease plant metabolism and growth may reduce weed control efficacy and crop tolerance. Such effects are transient and do not affect yield. Fertilizer top dressing will speed crop recovery.
General Use Precautions and Restrictions
- Preharvest Interval: Do not apply Granite GR within 60 days of rice harvest.
- Granite GR may not reliably control known ALS resistant weed biotypes.
- Applications made to greater than 3 leaf weeds, dense weed populations, and/or average water depth greater than 6 inches may result in reduced weed control.
- Do not apply Granite GR following rainfall until the water depth in checks or basins has been adjusted to meet the correct water depth requirements.
- Static water conditions for 7 days following an application of Granite GR are recommended for best results. It is important not to allow the minimum water depth to drop below 3 inches; therefore, adding water may be required. Water should be trickled in or added very slowly.
- For best results, it is recommended that water not be released for 14 days following an application of Granite GR. During this time water depth should be maintained or can be increased as rice grows. Early release of water may result in reduced weed control.
- Shallow water conditions can result in reduced weed control as it may promote additional weed flushes and can increase the potential for crop injury.
- Reduced weed control can be expected at field water inlets due to dilution and movement of water.
- Do not apply where runoff or irrigation water may flow directly onto agricultural land other than rice fields.
- The use of Granite GR on rice varieties with known reduced seedling vigor when established and grown under adverse weather conditions is not recommended. Use care when using Granite GR on newly released rice varieties until variety tolerance can be determined.
- Application of Granite GR to fields that have been leveled within 12 months prior to application may result in serious rice injury in areas that have been cut or filled. This does not apply to normal annual land planning activities. - Under poor field preparation practices (i.e., lack of soil aeration, unleveled ground, large clods, excessive crop residue, weeds emerged prior to flooding, etc.), reduced weed control may occur when using Granite GR.
- Cold and/or alternating weather conditions during the planting season can result in prolonged weed seed germination resulting in reduced weed control.
- Do not make more than 1 application or apply more than 18.5 lb of Granite GR (0.044 lb ai penoxsulam) per acre during the growing season.
- Do not apply Granite SC to the same field in the same year following an application of Granite GR.
- Do not rotate treated land to crops other than rice for 3 months following application.
- Do not use on wild rice.
- Do not fish or commercially grow fish, shellfish or crustaceans on treated acres during the year of treatment.
- Chemigation: Do not apply this product through any type of irrigation system.
Best Management Practices for Aerial Application
Equipment used in the application of Granite GR should be carefully calibrated before use and checked frequently during application to be sure it is working properly and delivering a uniform distribution pattern. Avoid overlaps that will increase Granite GR dosage above recommended limits. Aerial applications of Granite GR should not be made when the wind velocity exceeds 10 mph.
Application timing is dependent upon the proper rice growth stage and optimum timing for weed species present. Granite GR herbicide should be applied to rice after it reaches a minimum of 2 1/2 leaf stage (Figure 1); at this stage the second rice leaf is fully expanded or unfurled with third leaf emerged. Granite GR should be applied when susceptible weeds are from the 1 to 3 leaf stage up to 60 days before harvest. (See Application Rates and Weeds Controlled table.)
It is important that the stage of rice be closely monitored prior to application to determine the correct timing for an application of Granite GR. Under cool growing conditions, rice development can be delayed; therefore, close crop development monitoring is recommended prior to application.
The mode of action of Granite GR is the inhibition of the acetolactate synthase (ALS) enzyme. Weed populations may develop biotypes that are resistant to different herbicides with the same mode of action. If herbicides with the same mode of action are used repeatedly in the same field, resistant biotypes may eventually dominate the weed population and may not be controlled by these products. Other resistance mechanisms, such as enhanced metabolism, may also exist and may cause reduced weed control. Granite GR may not reliably control known ALS resistant weed biotypes.
This product should be used as part of an Integrated Pest Management (IPM) program that may include biological, cultural, and chemical practices aimed at preventing economic pest damage. Application of this product should be based on appropriate IPM and resistance management strategies and practices that delay or reduce the development of resistant weed biotypes. Such practices include, but are not limited to, field scouting, use of weed free crop seed, proper water management, correct weed pest identification, following rotational practices outlined on pesticide labels, and treating when target weed populations are at the correct stage and economic thresholds for control. Make only 1 application per acre per year of Granite GR. Do not apply Granite SC to the same field in the same year following an application of Granite GR.
To delay development of herbicide resistance, the following practices are recommended:
- Always use at least 15 lb per acre of formulated product and observe all label use rate instructions.
- The use of herbicides with the same mode of action should not be used in sequential applications.
- Herbicides should be used based on an IPM program.
- Monitor treated areas and control escaped weeds.
- Contact local extension or crop advisor for IPM and resistance management information.
Aerial Application for Selective Postemergence Weed Control in Rice (For Distribution and Use Only in the State of California)
Directions for Use
Refer to product label for General Use Precautions and Restrictions, Mixing instructions, and all other requirements not covered under the supplemental label.
For aerial applications of Granite SC, the applicator should follow all requirements in the supplemental label and guidelines in the Spray Drift Management, Aerial Application Requirement and Aerial Drift Reduction Advisory sections, in addition to the mandatory aerial buffers, to minimize potential drift to off-target vegetation. In general, the best drift management strategy is to apply the largest droplets that provide sufficient coverage and control.
Where states have more stringent regulations, they must be followed.
For specific details, refer in the supplemental label.
Stage of weed development: up to 3 leaf
Under conditions of late application when weeds are greater than 3 leaf stage, dense weed populations, or average water depth greater than 6 inches deep, 18.5 lb of Granite GR (0.044 lb ai penoxsulam) per acre may be applied. Application of Granite GR under these conditions may result in reduced weed control.
Ricefield bulrush (Scirpus mucronatus) and redstem (Ammannia spp) are effectively controlled if emerged at the time of treatment with Granite GR.