APPROVED HERBICIDES"It is vital for farmers to use herbicides approved by the Pest Control Products Board and, where necessary, take soil samples to the Kenya Plant and health Inspectorate services to determine whether it has been contaminated with the herbicides," said Mr Kuria.According to the World Health Organisation (WHO), the widely used 2,4-D
a key ingredient in a new herbicide developed by the Dow company "possibly" causes cancer in humans.
2,4-dichlorophenoxyacetic acid (2,4-D
) is a herbicide widely used in weed control in the world and our country.
Florasulam + 2,4-D
applied at the dose 3.75g a.i x [ha.sup.-1] + 180g a.i x [ha.sup.-1] at BBCH 30 followed by Kelpak applied three days later at a dose 2[dm.sup.3] x [ha.sup.-1];
In the Cerrado of Goias, the first application of 2,4-D
, and then another one exclusively with the herbicides carfentrazone-ethyl, paraquat, saflufenacil, paraquat + diuron or glufosinate-ammonium, resulted in regrowth percentage higher than 22% in 2013 and more than 18% in 2014.
Eight treatments consisted of seven increasing doses of 2,4-D
in the following concentrations: 187.5; 200; 212.5; 225; 237.5; 250; 262.5 mg [L.sup.-1] and the control obtained from artificial pollination with pollen.
The use of two auxins combined (2,4-D
and IAA) was not efficient for callus formation in internodal explants however, in leaf explants, the calli formation percentage reached 50%, corroborating Kakani, and Peng (2011), who found that for callus formation a combination of cytokinin and auxin is needed.
(10 mg L-1)###51.60###44.55###45.51###38.83###45.12A
Among plant growth regulators (PGRs) tested for callus induction, BAP (6-benzylaminopurine) in combination with 2,4-D
(2,4-dichlorophenoxyacetic acid) successfully induced callus from all the explant types.
The decision by the IARC to classify substances like 2,4-D
and glyphosate as potentially harmful is likely to cause alarm among farmers and consumers, who will wonder about the appropriateness of its continued use in commercial agriculture or gardening.
The IBA and 2,4-D
solutions were prepared by the dilution of the powdered product with NaOH 0.5 N and then adding distilled water to reach a final volume of 1 L.