-3-


Table 1. continued ..........


 Control Control
Treatments Lbs/A Kind of Weeds index 5/ in months

51. Karmex FW 40 + 40 Bernuda grass 7 10
52. 80 5 10
53. 80 + 80 / 9 12
5. MH-4O 3 "i 4 1
55. 3 3 V/ 7 3
56. 6 6 2
57. 6 +6/ "
58. Dalapon 25 10 6
59. 25 + 25 / 10o 6
60. 50o n 9 6
61. 50 + 50 / 7 6
62. Check 0 0 0


In 60 gallons per acre.
Applied in solid form.
In two applications; 25 to 30 days apart.
" 2.5 months apart.
Zero, no control; ten, complete control (grass killers were
brush and weed killers were not rated on grasses).


rated on grasses;


applied twice will control the grass satisfactorily. It nay be pointed out that the-
effect of Dalapon on the toxic residue in the soil is of relatively temporary nature,
which permits the growth of plants not belonging to the grass family one or two
months after treatment. The Karnex herbicides tend to remain in the soil for a long
period of time and in most cases no vegetation grows in the treated areas for six
months or more depending on the rate used.

 It was observed that rainfall run-off transported the Karmex herbicides to
lower locations in the field and in some instances susceptible valuable plants locat-
ed in low spots were seriously injured. Iost of the ornamental plants growing near
the treated area were susceptible to the effect of Karmex herbicides. The injury de-
pended on the amount applied or carried by rain to areas around the plants. When the
dosage was not lethal, peaches, papayas, guavas, mangoes, avocadoes, hibiscus, night
blooming jasmine, bougainvillea, and other plants exhibited marginal yellow patterns
which extended irregularly to the midrib and growth and production of fruit appeared
to be impaired seriously. Citrus plants, bananas, pineapples, amaryllis and gladiola
growing in the same vicinity seemed to be affected to a lesser degree or not at all.
The use of Dalapon under similar conditions (spraying the grass weeds around the
plants and shrubs) produced severe defoliation of most of the ornamental and fruit
plants listed above. This condition seemed to bring about failure to produce rapid
growth and fruit formation. These are preliminary observations only and need further
study to confirm the action of urea derivatives and Dalapon on fruit trees and orna-
mental plants.

 When low rates of Karmex W were used, excellent control of most weeds was
accomplished when mixed with Dalapon. Another promising mixture was 2 pounds of
2,$-D with 10 pounds of Dalapon, which controlled most weeds, not quite as effective-
ly as the high rates of Karmex W, but adequately enough to suggest its use. The mix-