COLLEGE OF SCIENCES
- A Short Course for People Using Herbicides
Time of Course and Venue:
The Understanding Herbicides course is designed primarily as a stand-alone course to give participants a good grounding in the principles of using herbicides to control weeds. It has been designed to prepare participants for working in the herbicide industry within New Zealand, but is also useful for people working in agriculture, horticulture and regional councils who need to control weeds with herbicides as part of their job.
Tuesday 3 August 2021 to Thursday 5 August 2021.
Coordinator: Dr Kerry C Harrington
School of Agriculture and Environment
This course is designed primarily as a stand-alone course to give participants a good grounding in the principles of using herbicides to control weeds. It has been designed to prepare participants for working in the herbicide industry within New Zealand.
On successful completion a participant should be able to understand herbicides well enough to be able to select the most appropriate compound for any weed situation and obtain maximum effectiveness from that herbicide without causing damage to crop plants.
All successful participants will receive an official certificate of completion and the material will count as 5-credits at 300-level towards a university qualification.
Topic 1 – Introduction:
Explanation of various things about the course; introduce participants to various terminology about herbicides in case they know nothing; herbicide mode of action.
Topic 2 – Herbicide toxicity and legislation:
Safety testing of herbicides; relative toxicity of herbicides; New Zealand legislation; withholding periods; the GROWSAFE scheme; the 2,4,5-T and glyphosate controversies; herbicide residues in food.
Topic 3 – Herbicide formulation:
Solutions; emulsions; wettable powders; granules; dusts; surfactants; chemical drift through the air; common and trade names; calculations.
Topic 4 – Behaviour of herbicides in plants:
Interception and uptake of foliage-applied herbicides; availability and uptake of soil-applied herbicides; transport of herbicides in the plant; factors affecting these processes; herbicide selectivity.
Topic 5 – Behaviour of herbicides in the soil:
Adsorption; volatilization; leaching; photochemical degradation; chemical decomposition; microbial decomposition; rates of degradation of herbicides; bioassays; activity of soil-applied herbicides; selectivity of soil-applied herbicides; effects of weather on herbicides.
Topic 6 – Herbicide application:
Conventional spraying equipment; calibration of a sprayer; back-pack sprayers; problems with conventional sprayers; improvements in spraying equipment; wiper applicators.
Topic 7 – Knockdown herbicides:
Characteristics of importance in decision making; broad-spectrum herbicides; translocated knockdown of dicots in grass crops; contact knockdown of dicots in grass crops; selective knockdown of grasses in dicot crops; sulfonylureas; other knockdown herbicides.
Topic 8 – Residual herbicides:
Residual herbicides used primarily for non-selective control; herbicides used primarily for depth protection; selective residual herbicides which primarily control dicots; selective residual herbicides which primarily control grasses.
Topic 9 – Economics of weed control:
When weeds reduce yields through competition; when weeds exert indirect effects in pasture; when weeds cause other effects difficult to measure; how most weed control decisions are made.
Topic 10 - Weed control in pastures and lucerne:
Problems caused by weeds; keeping pastures competitive; discouraging weeds that establish; weed control in new pastures; weed control in established pastures; control of specific problem weeds; clearing scrub weeds; weed control in riparian plantings; weed control in lucerne using management; weed control in lucerne using herbicides.
Topic 11 – Weed control in annual crops:
Obtaining weed control information; cereals; maize and sweet-corn; forage brassicas; fodder beet; peas.
Topic 12 – Herbicide resistance:
Sexual vs vegetative reproduction; advantage of genetic variability; development of ecotypes; development of herbicide resistance; rate of herbicide resistance development; using herbicide resistance; examples of herbicide resistance problems in New Zealand.
Cost: $1500 + GST (includes study guide, 3 days of lectures, morning and afternoon tea and lunches, venue hire at Massey University)
Participants should arrange their own accommodation in Palmerston North. The course begins 8.30 am Tuesday, but is finished by 3.00 pm Thursday which should allow participants to travel home that day.