Baldwin, Richard L. : Richard L. Baldwin, Ventura and San Diego counties

Breece, James R. : James R. Breece are Farm Advisors, Ventura and San Diego counties

Cudney, David W.

Gibeault, Victor Victor

thatch removal . In the experiment , thatch The purpose of our experiment was to Kikuyugrass , Pennisetum clandestinum was removed 48 hours after treatment to evaluate the use of glyphosate to control es - Hochst . ex Chiov . , was introduced into minimize the time that the turf area would be tablished kikuyugrass , followed by the estab - California about 60 years ago as a turf and unavailablefor recreationaluse . Previousun - lishment of a competitive cool - season grass erosion - control species . It is a native of reported work by the experimenters has that would allow preemergence use of eastern and southern Africa and is now indicated that 48 hours is sufficient for ade - siduron to control germinating kikuyugrass found in such wide - ranging areas as Colom - quate kikuyugrass control . seedlings . bia , New Zealand , Hawaii , and Brazil . This of the three main blocks was then Each perennial grass has become established in Turf trials split into three and reseeded with one of the California from the Mexican border to San following turf species at rates per 1 , OOO The experiment was established in 1978 at Fransicso Bay . Stands are confined almost square feet : â?? Derby â?? perennial ryegrass at 6 two sites within 3 miles of the coast , sepa - entirely to coastal areas where minimum pounds ; â?? Alta â?? tall fescue , 10 pounds ; and rated by 200 miles . The Ventura County trial 60 â?쳌 F . average temperatures are above â?? Fylking â?? Kentucky bluegrass , 3 pounds . The was begun in September on a silty clay soil Kikuyugrass is a vigorous competitor in sub - blocks were further split into four plots and the San Diego trial in October on a sandy turfgrass and crowdsout desirablespecies . It each for treatment : no siduron ; siduron ap - loam soil . Both sites had adequate phos - develops an undesirable thatch of rhizomes plied preemergence ; siduron applied pre - phorus and potassium . The trials were de - or stolons . When managed properly , kikuyu - emergence and repeated in February ; and as a split - split plot arrangement with signed grass can be a desirable turf with good color siduron applied preemergence and repeated and high durability , but it is usually con - three replications . in February and July . Each siduron applica - There were three main blocks : no glypho - sidered a weed in golf courses , bowling tion was at 12 pounds active ingredient per sate treatment ; one glyphosate treatment ; greens , and some home lawns . It resembles acre in water at 30 gallons per acre with the a and one glyphosate treatment followed by St . Augustinegrass , Stenotaphrum secun - CO , pressurized backpack sprayer . second treatment two weeks later . All gly - datum ( Walt . ) Kuntze . , and has been After the three cool - season turfgrass phosate treatments were applied at 4 pounds mistakenly propagated as that desirable species became established , they were active ingredient per acre with a CO , pressur - species . regularly irrigated and fertilized with soluble 35 psi with ized backpack sprayer operated at There are sterile and fertile types of kiku - nitrogen to maintain good turf quality . The a spray volume of 30 gallons per acre . yugrass . Since the fertile type predominates , a lfi - inch test sites were mowed weekly at Normally a waiting period of seven days is seedlings , as well as the established peren - cutting height . No other primary or second - advised after glyphosate treatments before nials , usually must be controlled . Chemical and cultural control of kikuyugrass in turf David W . Cudney 0 Victor A . Gibeault 0 Richard L . Baldwin 0 James R . Breece Kikuyugrass crowds out desirable turf species and develops an undesirable thatch of rhizomes or stolons . 4 CALIFORNIA AGRICULTURE , JANUARY - FEBRUARY1982 TABLE 1 . Kikuyugrasscover at two California sites treated with 0 = Kentucky bluegrass Go = no glyphosate 1 % years after initial treatment glyphosate or siduron , rated G , = 1glyphosatetreatment I = Perennial ryegrass Kikuyugrassrating't at : So = no siduron Herbicide Ventura San Diego = Tall fescue S , = 1 siduron treatment GLYPHOSATE TREATMENT : 9.4 y 7.8 y None 2.8 z 5.1 z One 2.7 z 4.4 z Two l80I SIDURON TREATMENT : None 6.4 y 6.5 y One 4.5 z 5.5z Two 4.7 z 5.5z Three 4.2 z 5.5z $ 2 TABLE 2 . Kikuyugrass cover as influenced by glyphosate and 1 % years after first application siduron treatmentsat Ventura , G S o G S i GoSi GoSo Kikuyugrassrating * t Herbicidetreatments Siduron GIyphosate treatment Fig . 1 . Cumulative effect of kikuyugrass control ( 0 = no weed treatment None One Two cover : 10 = 100 % cover ) 1 % years after first treatment , Ventura . None 9.7 z 4.7 y 4.8 y 9.2 z 2.1 z 2.1 z One lot 9.3 z 2.7 z 2.2 z Two 9.2 z 1.9z 1.6 z Three TABLE 3 . Kikuyugrass cover at two Californiasites overseededwith three cool - seasonturfgrasses , rated1 % years after herbicide treatment , A , : : : . 5Ix : Kikuyugrass rating * t . : . : . : . : . . . . . . Turfgrass Ventura San Diego . & . : . : . x . . . . . . . . Kentucky bluegrass 5.8 y 7.5 x . : . : . : . . : . = . . : . . w : . : . : . . . . . . . . Perennial ryegrass 4.5 z 4.0 z . . . , : . < : LGSIgc ' . . . . . . . , . . , : : : * I : . : . : . : . Tall fescue 4.6 z 5.8 y GSo GoSi GQSQ ' Kikuyugrass cover rating on a 0 to 10 scale , with 0 representing no kikuyugrass and 10 representing 100 percent kikuyugrass . Herbicidetreatments tValues in a column followed by the same letter are not significantly different at the 5 per - Fig . 2 . Cumulative effect of kikuyugrass control ( 0 = no weed cent level according to Duncan's multiple range test . Data are analyzed across all cover ; 10 = 100O / 0 cover ) 2 % years after first treatment , Ventura . treatments . cover ratings six weeks after the Ventura trial 1 ) . At ment at Ventura and San Diego ( table ary turfgrass maintenance was performed on was seeded . Perennial ryegrass and tall both sites , there was no significantdifference the two sites . of 6.9 and 7.7 , respec - fescue , with ratings in kikuyugrass reinvasion among one , two , Kikuyugrass cover ratings were made over tively , covered the plots significantly more or three siduron treatments , which demon - a 30 - month period after the trial began . quickly than Kentucky bluegrass , with a 3.7 strates the importance of applying siduron at Kikuyugrasscover was evaluated on a 0 to 10 rating . the time of renovation . Apparently kikuyu - scale with 0 representing no kikuyugrass and The best combination of treatments in grass begins reestablishment right after the 10 representing 100 percent cover . All data 1and 2 ) 2 % years after applica - Ventura ( fig . glyphosate / thatch - removal / over - seeding were subjected to statistical analysis and tion of glyphosate to control established treatment , so siduron is needed immediately . mean separation using the Duncan's multiple kikuyugrass was overseeding with tall fescue The importance of glyphosate in the com - range test . followed immediately by one or more treat - 2 ) , bined treatments is readily apparent ( table Results and discussion ments of siduron for kikuyugrass seedling because plots receiving no glyphosate treat - control . Kentucky bluegrass grew slowly and ments were entirely covered with kikuyu - At both San Diego and Ventura , either one proved to be a poor choice for kikuyugrass of the siduron treatments . grass , irrespective or two applications of glyphosate resulted in renovation . Perennial ryegrass equaled tall Any combination of glyphosate and siduron significantly less kikuyugrassreinvasion than 1 % years after glyphosate treatment fescue produced the greatest decrease of kikuyu - no no glyphosate treatment , but there was but was weakened , because of low mainte - significant difference between the two herbi - grass cover . nance levels , and eventually reinvaded by ki - Perennial ryegrass and tall fescue , which cide treatments ( table 1 ) . At both test sites , kuyugrass after 2 % years . germinate and become established much practicallyno kikuyugrassrecovered after the more rapidly than Kentucky bluegrass , re - first and before the second glyphosate ap - sulted in significantly less reinvasion of plication , which would account for the lack 1 % years following herbicide kikuyugrass of difference between the two treatments . David W . Cudney is Weed Scientist , and VictorA . treatments ( table 3 ) . Evidently , initialcompe - Siduron also affected kikuyugrass reinva - Cooper - Gibeault is Environmental Horticulturist , ative Extension , University of California , River - of the overseededgrassesis very impor - tition sion , primarily by limiting seedling germina - L . Baldwin and James R . Breece are side ; Richard tion . All siduron treatments resulted in tant in reducing kikuyugrass regrowth . This Farm Advisors , Venrura and San Diego counties , conclusion is further supported by turfgrass respectively . significantly less kikuyugrass than no treat - CALIFORNIA AGRICULTURE.JANUARY - FEBRUARY 1982 5