Carrot seedlings were coated with a biopolymer gel containing cells of Serratia entomophila. The coated seeds were either placed in polystyrene bags for stability testing and stored at 4 and 20oC or sown into large pots as shown below.
Bacterial viability (Serratia entomophila) on carrot seed stored at 4oC and 20oC
When stored under refrigeration (4oC) bacteria survived on the seed coat with little loss in viability over the full test period. High levels of viability were maintained on the seed for at least two weeks at 20oC. The results indicate that coated carrot seeds can be stored for extended periods under refrigeration and suggest that bacteria will survive at periods of higher temperatures for distribution.
Bacteria coated and untreated carrot seeds were sown into pots containing grass grub larvae and held in a controlled temperature room at 23oC under artificial light. After 5 weeks 75% of the treated carrot seeds had germinated, emerged and grown into small plants. From untreated seeds, maximum emergence was 40% and many of the small weakened plants had died after 5 weeks.
Treated carrot seed has been used to protect seedlings from damage in commercial growing of organic carrot seed crops in Canterbury.
Carrot seedlings establishing from coated and untreated seeds in the presence of grass grub larvae.
Seedling protection from grass grub with S. entomophila coated seeds. Untreated seeds (above) and pots containing larvae to the left.
