Submitted to: Pesticide Formulation and Application Systems Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 28, 2002
Publication Date: October 16, 2002
Citation: Collins, R.T., Helling, C.S., Camp, M.J. 2002. Development of a soil applied herbicide system for season long control of opium poppy. Pesticide Formulation and Application Systems Symposium Proceedings.
Growing Opium poppy for the production of heroin is an ever-increasing problem in Colombia. If growers expect their poppy to be sprayed with glyphosate, they will plant only part of their field. After the spraying, the whole field will be replanted. To eliminate the need to reapply glyphosate to poppy fields, research was conducted to develop a soil applied herbicide system in which one application would eliminate poppy production for the remainder of the growing season. The experiments were conducted at the Weed Science Laboratory field site near Kapaa, Hawaii in 2000 and 2001. This location was selected because of the high level of year round soil microbial and chemical activity for herbicide breakdown. Four herbicides (bromacil, diuron, hexazinone and terbacil) were evaluated. Five formulations were tested for each herbicide: spray solution either from wettable powder or liquid, spray solution of micro-capsules, 5% granule, 1/4 coated 5% granule and 1/12 coated 5% granule. Each formulation was evaluated at one and two kg/ha. The experiment consisted of 40 treatments plus the control. Each treatment was replicated 4 times. Poppy seeds were planted in the treated areas every thirty days, beginning within 3 days of herbicide application. The numbers of seedlings were counted, 21 days after planting. The percent mortality was analyzed at 2, 3 and 4 MAT. Two treatments gave equally efficient and consistent control at all the evaluation periods. Bromacil and terbacil 1/12 coated 5% granules at 2 kg/ha averaged 97.3 and 97.7% control of opium poppy. The goal of developing a soil applied herbicide system for long-term control of opium poppy was achieved. Field-testing of these two treatments in poppy growing regions will be necessary to determine if season long control has achieved.