22 CATTAILS 



CONTROL 



Cattail stands can be controlled effectively by herbicides, mow- 

 ing, or other mechanical means. The species of cattail and the 

 local habitat conditions commonly have a bearing on effectiveness 

 of treatments. In general, the optimum stage for treatment is 

 about the time flowers of the staminate spike are drying. On lim- 

 ited areas, invading seedlings can be eliminated effectively by 

 hand pulling. 



New herbicides, particularly ATA and dalapon, have largely 

 supplanted 2,4-D in recent control operations. Though 2,4-D was 

 used widely for this purpose formerly, it was not particularly satis- 

 factory since a number of retreatments have usually been necessary. 

 Tests with the new herbicides will need to be continued for several 

 more years before positive conclusions can be made about the best 

 method of treatment for the different species in different environ- 

 mental conditions. 



ATA has given uniformly good to excellent results in California 

 (Citrus Experiment Station, Riverside) and Maryland (FWS 

 Patuxent Research Refuge, Laurel) at rates of 5 to 10 pounds active 

 ingredient per acre. Dalapon at 20 pounds acid equivalent has 

 given complete control in Michigan tests (Grigsby et al., 1955) 

 and at the St. Marks Refuge in Florida, but in a Maryland site 

 periodically flooded by tidewater 40 pounds failed to kill all of the 

 plants. At present it appears that dalapon is much more likely 

 to be effective on comparatively dry sites than in flooded habitats. 

 In southern California, two dalapon treatments (May and Septem- 

 ber) at 10 pounds each, followed by midwinter burning of dead 

 stems, failed to prevent considerable regrowth of cattails. Mix- 

 tures of ATA (50% commercial formulation) and dalapon (S5% 

 commercial formulation) at respective approximate poundages of 

 3 and 6 have been used in 100 gallons of water applied at the rate 

 of 400 to 500 gallons per acre in southern California. 



Cutting cattails close to the ground at two special stages of 

 growth in the same season resulted in 90% to 100% control in 

 Maryland, Tennessee, and Utah tests. The first cutting should be 

 made when pistillate spikes are well formed and at least two- 

 thirds full size but not mature enough to scatter viable seeds ; the 

 second about a month later, after regrowth has attained a height 

 of about 2 feet. Cutting at other times was found to reduce 

 greatly the percentage of kill. Success is likely to be greater in 

 areas where water is present and covers the cut stem-bases, yet 

 even where water is absent much of the time, as in some tidal or 



