Recommendation - treating conifer plants at the time of planting using Marshal/suSCon Granules. The product contains 10% w/w carbosulfan and 10 grams should be placed in the planting hole when planting.
Incitec International developed the suSCon granules to extend the period of activity of non-persistent insecticides. The micropore structure of the polymer based granules enables the gradual and controlled release of the active ingredient over specified periods. The insecticide in this case is carbosulfan which is released over a two-year period. Once in the soil the insecticide degrades but is constantly replenished from the granules.
Ten grams of Marshal/suSCon is applied to the root zone at time of planting. The granules must not remain on the surface of the soil where they would be both ineffective and be hazardous to wildlife. When the active ingredient is released into the surrounding soil, it is rapidly taken up by the roots of the young trees. Chemical analysis has shown that the highest active metabolite concentration occurs in the lower stem region. This is where Hylobius are more likely to attack.
Experiments have demonstrated that a single application of Marshal/suSCon provides protection for a period of at least two years. However, because it takes several days for the trees to absorb sufficient active ingredient to ensure full protection, a top spray of transplants is advisable immediately after planting. Alternatively, plants may be treated before planting by either the Electrodyn or by spraying container grown plants. Because the insecticide is rapidly degraded in the plant tissues, it is not possible to obtain lasting protection by treating bare-rooted plants in the nursery beds before lifting. The granules may be effectively used in mixture with the growing medium, but the mix should not be used for germinating seeds. It is important to remember that the time taken for growing plants in the mixture in the nursery will reduce the effective life of the product in the field and additional post-planting sprays of alpha-cypermethrin may be required for full protection.
Marshal/suSCon is effective in protecting a range of UK conifer species and no phytotoxic effects have been seen apart from with very young seedlings. Marshal/suSCon sachets are packaged in water-soluble sachets designed to break down after application, delivering a pre-measured dose of granules in to the root zone.