Basamid
General Information
BASAMID GRANULAR is a general purpose soil fumigant suitable for preparing seed beds to grow vegetables, tobacco, ornamental and forest tree seeds (e.g. to prevent clubroot in brassica seedbeds) or as a disinfectant before planting out tomatoes, brassicas, lettuces, cut flowers, strawberries or before replanting fruit trees or laying down areas of turf (e.g. golf greens).
BASAMID GRANULAR can also be used to disinfect bulk soil. It can be used in glasshouses, cold frames or out-of-doors, and by the home gardener as well as the commercial grower.
BASAMID GRANULAR is easy to apply by hand (using rubber gloves) or through suitable applicators as it is formulated as a granule or prill. Gas release occurs several hours after incorporation and contact with moisture, preventing discomfort to the operator.
BASAMID GRANULAR controls, by fumigant action, nematodes, soil inhabiting insects, soil fungi, many annual weeds and germinating weed seeds, and affords moderate control of Oxalis spp.
BASAMID GRANULAR has no long-term toxic effect and planting may normally resume 3-4 weeks after treatment. After gas release the soil can be checked for suitability for planting by means of a simple germination test (cress test).
Mode of Action
On contact with soil moisture BASAMID GRANULAR is transformed into gaseous active compounds, which penetrate the spaces between soil particles. Soil organisms, including most micro-organisms and plants, are susceptible to these gases and are destroyed primarily by the action methylisothiocyanate, and to a certain extent by carbon disulphide. Formaldehyde, hydrogen sulphide and monomethylamine also play a role.
Direction for Use
Soil:
The soil to be treated with BASAMID GRANULAR should be well prepared and be: in seed bed condition with a finely structured surface; completely free from undecomposed roots and of plant residues; in a moist state (field capacity) at least 7 days prior to treatment. Watering is absolutely necessary when the soil is low in moisture content; the soil should not be saturated at the time of incorporation; optimum soil temperatures are between 10C and 32C.
Application Rates:
The rates are based on:
(a) Glasshouse and outdoors application to 20-30 cm in soil depth.
For the control of free living nematodes, most root disease causing fungi, soil insects and insect larvae, weeds and weed seeds:
On light soils 400-440 kg/ hectare (400 g/10 m2)
On loamy soils and soils rich in organic matter 500-550 kg/ hectare (500 g/10 m2)
For the control of cyst forming nematodes (Heterodera spp.) as Verticillium albo atrum and Fusarium oxysporum var. cubense infested soils:
On light soils 550 kg/ hectare
On loamy soils and soils rich in organic matter 660 kg/ hectare
Soils infested with wilt disease agents (Vertcillium albo atrum, Fusarium oxysporum) should be fumigated to a depth of 30 cm. If mainly weed control is desired BASAMID GRANULAR should be incorporated 10 -15 cm deep. Then a rate of 280 kg/hectare (280 g/10 m2) is adequate provided annual weeds are to be controlled and perennial weeds and rhizomes are not present. The treated are can be sprinkler-irrigated to increase the effectiveness in some soils to prevent soil surface drying out.
(b) Bulk soils for nursery use:
BASAMID GRANULAR can be used to treat large or small quantities of bulk soils. With the large quantities BASAMID GRANULAR should be spread at 60 g/m2 over every 25 cm thick layer of soils as the heap is made up and thoroughly incorporated into this layer. This is repeated every 25 cm until the heap is completed, then cover with polythene and leave for 3 weeks. Alternatively use 200 g per cubic metre of soil i.e. 20 g/litre (cubic decimetre). For small quantities BASAMID GRANULAR can be incorporated and mixed by adding the required amount of granules to the soil and mixing with a soil shredder, placing the soil in polythene sacks, sealing and leaving for at least 3 weeks away from house and plant life before opening.
BASAMID GRANULAR can also be worked into the soil with a spade or a hoe. The effectiveness decreases, however, when the fumigant is not mixed thoroughly with the soil. Higher doses should therefore be used to compensate for poorer soil incorporation when a hoe or spade is used.
Distribution and Incorporation
BASAMID GRANULAR must be evenly distributed on the soil surface. This can be done by hand (with rubber gloves) or by fertiliser spreader. Immediately after spreading, BASAMID GRANULAR must be thoroughly worked into the upper 15-23 cm of the soil. Best results are obtained when a rotary cultivator with L-shaped tines is used. The rotor speed should be high and the tractor should be driven in low gear.
With both methods the soil must be at field capacity at the time of treatment for adequate activity. If soil is dry before treatment we with 5 -10 litres of water per square metre seven days before treatment.
Sealing of the Soil Surface
To prevent the toxic gas from escaping from the soil the surface must be sealed. Polythene sheets are the most efficient means of sealing. Rolling - use a heavy flat roller and the seal formed must be maintained by rainfall or irrigation. Water- sufficient water must be applied to compact the soil and form a surface crust. It is essential that the soil surface be maintained in a moist condition until the gas release is complete and the granules have completely disappeared.
Aeration of the Soil
This can be done by rotovator, by a disc plough or by hand tools (double digging). The soil should be worked no further than depth of incorporation of BASAMID GRANULAR. With cool temperatures (below 10C) the soil should not be worked for at least 3 weeks. With moderate temperatures, open no earlier than 10 days. Best results can be expected when the soil surface is kept sealed for several months and aeration is delayed until the ground is required for planting.
Note: Only clean disinfected tools should be used. Disinfect tools and machines by washing with a formaldehyde solution. Also wash boots before entering fumigated soil.
Planting
All traces of toxic gases must have disappeared from the soil before sowing or planting is possible. With soil temperatures of 10C 3-6 weeks are necessary, with soil temperatures above 20C 14-21 days are often sufficient for the gases to disappear after aeration. The readiness of the soil for planting can be verified with the following germination test (Cress test): Take soil samples from both treated and untreated soils at a depth of 10 -15 cm by scraping the surface soil aside and quickly filling a jam jar with a screw top to the three-quarters mark and immediately close the jar. Place moist cottonwool pads, with cress (lettuce) seeds in the jars, opening them for as short a time as possible. Place the jars in a room at about 22C. Check 48 hours later whether seeds have germinated. If the seeds have germinated in the jar with the untreated soil, but not in the jar with the treated soil, the toxic gases have not yet escaped from the treated soil and the soil should be worked again to aerate it.
Note: Transplants to be planted on fumigated soil should be raised on clean, disinfected soil. Otherwise there is a danger of carrying nematodes and disease agents on the fumigated soil, which may spread rapidly and nullify the effect of the fumigation. Read the specific leaflet on BASAMID GRANULAR for detailed information.
Fertiliser
Chemical sterilisation releases nitrogen and the fertiliser programme should be adjusted accordingly.
Toxicity
Harmful substance. Acute oral LD50 (rat) 519 mg/kg. Acute dermal LD50 (rat) >2000 mg/kg.