Metalaxyl and glyphosate are generally not recommended to be mixed together directly in a tank due to differences in their chemical properties and target usage:

1. Compatibility: Metalaxyl is a systemic fungicide targeting oomycete fungi, while glyphosate is a non-selective herbicide used to control weeds. Mixing the two can sometimes lead to reduced effectiveness or incompatibility, such as poor emulsification or uneven spray distribution.
2. Application Timing: Metalaxyl is usually applied at planting or early in the season to control fungal diseases, whereas glyphosate is often applied later for weed control when crops are actively growing or close to harvest.
3. Potential for Crop Injury: The combined use may increase the risk of phytotoxicity or crop damage, especially for young plants or in sensitive crops, as glyphosate can stress plants, making them more vulnerable to other chemicals.
4. Best Practice: If both fungicide and herbicide treatments are needed, it’s advisable to apply them separately. This allows each product to perform optimally and reduces the risk of antagonistic effects.

For effective application, always refer to the manufacturer’s label instructions and consult agricultural experts for advice tailored to specific crops and growing conditions.