Staggered crop emergence is common after variable rainfall or uneven sowing conditions - and it presents a real challenge when it comes to spray timing. In these situations, some plants may be at the ideal growth stage for herbicide or fungicide application, while others lag. Spraying too early can miss later-emerging weeds or damage younger plants, while waiting too long may allow early weeds or disease to get ahead.
To manage this, it’s essential to strike a balance between protecting your crop and maximising the spray’s effectiveness. Work with your agronomist to assess the paddock carefully. Consider prioritizing the dominant growth stage, using selective chemistry with good crop safety margins, and in some cases, splitting applications to match crop development. A well-timed spray, even in uneven crops, can preserve yield potential and avoid unnecessary crop stress. Remember, it’s not just about what’s in the tank—but when and where it’s applied.
Agronomy is often a compromise between several factors. This year we will often face a compromise between effective weed management, crop safety, disease management, economics, and practicalities.
Utilising products and mixes that have a wide registered application window is a good strategy. With herbicides, select products that can be applied from the cotyledon or 2-leaf stage and can extend to Z31 in cereals or beyond.
The bulk of your yield is most likely to come from the early emerged plants or zones but don't forget about or dismiss the later emerging plants or zones. These areas can still be prone to early insect damage as they are young and vulnerable. There have been reports of beetles, mites, and lucerne flea attacking these later plants. Although these plants have started the game slow, they may still be able to kick the winning goal if the season ends favourably.
The varied growth stages in crops this season can also present a challenge for timing nitrogen application. Work with your agronomist to assess yield potential in each paddock or zone. Then assess your return on investment for your targeted nitrogen rates required. The bulk of the yield is likely to come from the most advanced areas, so ensure you feed them accordingly. We never like to waste money in any season, but you can rest a bit more comfortably now with the latest research indicating that nitrogen not utilised by the crop this season will be available for the next crop.
Timing fungicide applications can also be a challenge. Again, we need to protect the most advanced yield-producing plants or zones. Stick with your pre-cropping plan and be strategic with fungicides. Fungicides are protectants and need to be applied before disease infection to be most effective and to provide the longest length of protection. Some fungicide is always better than no fungicide if an outbreak occurs and the budget is tight. Consider tank mixes with a more cost-effective fungicide with your herbicides. This will save on application costs, which may be more than the cost of a fungicide.
As always, don't hesitate to get in contact with your local Crop Smart rep if there is anything we can assist with.