Rapeseed producers are advised to apply plant growth regulators to crops with high growth rates.

       It is recommended that canola growers apply plant growth regulators (PGRs) to the fastest growing canola crops to maximise yield and plant stability.
       This fall, plants vary not only in size, but also in stages of development: from plants with six true leaves to plants with only cotyledons.
       Therefore, management will become more complex and will require a site-specific approach,” said Nigel Scott, regional technical manager at Procam.
       Despite farmers’ reluctance to invest, some missed out on a bumper harvest last summer due to lack of investment and poor harvests the previous season.
       So why do agronomists report such inconsistent yields? Looking back over the past decade, Nigel points out that the average sowing date is the third week of August.
       However, due to the threat from cabbage stem flea beetles, sowing dates were moved earlier or postponed to avoid a situation where the crop is in the cotyledon stage when adult flea beetles appear at the end of August.
       This year, sowing was completed earlier in some places. He pointed to his county, Durham, where, like other parts of England, the harvest was completed ahead of schedule.
       Plants with access to water grow quickly. However, in areas with water shortages or dry soil, germination time increases.
       Thus, crop growth varies depending on water availability; some crops grow four, five, or six true leaves, while others grow only cotyledons.
       The last batch of plants planted after the September migration has so far produced only one true leaf. What’s worrying is that Nigel has begun to notice a large number of adult insects.
       “So, even in the same field, we observed plants at three different stages of growth.”
       For early-ripening crops, his farmers plan to use plant growth regulators—something they haven’t done for a long time.
       He noted that farmers need to use plant growth regulators (PGRs) now to maximize their effectiveness before it is too late.
       Ideally, this fertilizer should be applied when the plant has four to six true leaves (mid-October). Growth regulators can suppress the growth of above-ground parts and promote rooting (see diagram).
       This is explained by the fact that the longer the petiole, the lower the risk of the disease spreading to the stem and causing ulcers.
       ”This problem occurs more often in small plantations treated with fungicides such as difenoconazole.”
       Finally, he advised fertilizing slow-growing crops because soil temperatures will drop and they will need to accumulate biomass in preparation for winter.
       ”Even mature crops require certain nutrients, especially manganese and boron, to produce maximum yield.”
       One of the main challenges this fall is determining the optimal time to apply clethodim for weed control, given the wide variety of crops grown.
       Timing pesticide application is challenging because it can damage large areas of crops. “Therefore, farmers need to pay close attention to application timing,” Nigel said.
       He also suggests that increased residual nitrogen levels in the soil due to the summer drought promoted plant growth. Rising soil temperatures also imply increased mineralization.
       ”Buckwheat grows taller than rapeseed, and due to competition between crops, it also displaces rapeseed. Without buckwheat, rapeseed wouldn’t grow as tall.”