Seed certification - lifting dates - Netherlands
To avoid virus infection when aphid populations increase late in the growing season, haulm destruction dates are fixed each year for each variety, class and region.
Haulm destruction dates are based on:
- presence and activity of aphids.
- susceptibility of the variety.
- stage in crop growth - maturity resistance.
- infection sources present.
Haulm destruction dates are early when: many aphids are present, the variety is susceptible to viruses, crops are young and many infection sources are present in the area or crop.
HAULM KILLING/LIFTING DATES: '95-'97
The inspection service - NAK issues an advised haulm destruction date and a final haulm destruction date.
The final date for basic seed should generally be no later than the advised date for the next class.
Crops not harvested (or haulm not destroyed) at the final date are downgraded to a lower class.
Crops with re-growth after haulm destruction are very susceptible to virus !!!!!!!!