Non-Peer ReviewedIn 1987 a questionnaire survey was conducted to determine the distribution of the noxious weed scentless chamomile on the Black and Gray soils of Saskatchewan. As well information was obtained on the year of first sighting, habitats affected, farmers' perception of the problem, the percentage of their land affected, and methods used to control or manage the weed. A total of 29,666 questionnaires were distributed, of which 2120 (7.1 %) usable responses were returned. Of these, 35.6 % indicated that scentless chamomile occurred on land they farmed or on adjacent roadsides. In the group which reported occurrence the most common habitat, reported by 69.5 %, was the roadside. Annual crops were reported as scentless chamomile habitats by 30.0 % and wet areas of fields, which can sometimes be cropped, by 39.0 %. The most common methods reported for control of the weed were tillage, hand-weeding and herbicide use. Of the 214 farmers who indicated herbicide use, 26.2 % used herbicides containing bromoxynil, 16.4 % used herbicides containing dicamba and 15.4 % used glyphosate. Spread of the weed has increased rapidly in the last 20 years. Of the responses to year of first sighting 19.0 % were between 1968 and 1977, and 69.0 % reported first sighting the weed within the last decade

Douglas, D.W.

Thomas, A.G.

English

University of Saskatchewan Research Archive

Distribution and Rate of Spread of Scentless Chamomile on the Black and Gray Soils in Saskatchewan. D.W. Douglas and A.G. Thomas Agriculture Canada Research Station Regina, Saskatchewan ABSTRACT In 1987 a questionnaire survey was conducted to determine the distribution of the noxious weed scentless chamomile on the black and gray soils of Saskat-chewan. As well information was obtained on the year of first sighting, habi-tats affected, farmers' perception of the problem, the percentage of their land affected, and methods used to control or manage the weed. A total of 29,666 questionnaires were distributed, of which 2120 (7.1%) usable responses were returned. Of these, 35.6% indicated that scentless chamomile occurred on land they farmed or on adjacent roadsides. In the group which reported occurrence the most common habitat, reported by 69. 5%, was the roads ide. Annual crops were reported as scentless chamomile habitats by 30.0% and wet areas of fields, which can sometimes be cropped, by 39.0%. The most common methods reported for control of the weed were tillage, handweeding and herbicide use. Of the 214 farmers who indicated herbicide use, 26.2% used herbicides containing bromoxynil, 16.4% used herbicides containing dicamba and 15.4% used glyphosate. Spread of the weed has increased rapidly in the last 20 years. Of the responses to year of first sighting 19.0% were between 1968 and 1977, and 69.0% reported first sighting the weed within the last decade. INTRODUCTION The weed scentless chamomile (Matricaria perforata Merat) was declared noxious in Saskatchewan in 1977. Pressure from concerned farmers, especially from those in the east-central part of the province, was instrumental in this process. They were concerned that a weed for which there was not adequate chemical control was spreading at a rapid rate. Scentless chamomile is a showy weed when mature. It has a daisy-! ike flower, with white petals and bright yellow disc florets, which it produces in great number. The leaves are delicate and finely-dissected. Individual freegrowing plants can be 80 em tall and occupy an area having a similar diameter.This weed can exist as an annual, a winter annual, a biennial or as a short-lived perennial. It is primarily spread by movement of seed, of which 204 it is a prolific producer. Some limited spread can occur when whole plants are translo.cated on machinery. The plant has a large system of fine roots which, if sufficient moisture is present, can hold enough soil to support it through such transplantation and allow it to re-establish. A research project began in 1985 at the Agriculture Canada Regina Research Station to provide the background information necessary for the development of an integrated program of cultural, chemical and biological control. An impor-tant part of the research is determining where the weed occurs. This investi-gation has two aspects. The first is to establish the geographical distribu-tion of the weed in the province. This would show us whether we are dealing with a localized or with a widespread problem. Secondly, the habitats affected by scentless chamomile must be determined in order to evaluate the applicability of potential control measures. In this paper we will present the results of a survey conducted to determine these distributions. MATERIALS AND METHODS Previous records of occurrence of scentless chamomile in Saskatchewan were concentrated in the black and gray soils. We thus directed our resources toward further investigation of these areas (Figure 1A). We felt that the most effective method of surveying the very large areas involved was to ask those most familiar with the land - the farmers them-selves. A questionnaire package was prepared, consisting of the question-naire, a description and colour picture of the weed and a postage-paid return envelope. The questionnaire was short and straightforward. Our hope was that this format and the postage-paid envelope would encourage farmers to respond. Packages were mailed in the last week of July, timed to arrive when the weed would be conspicuously in bloom and before farmers became wholly occupied with harvest. Topics covered by the questionnaire included presence or absence of the weed, year of first sighting, habitats, a weed problem rating, percentage of land affected and control measures attempted. Included as well was a request for specific quarter-sections affected. This information, with the year of initial infestation, was used to map the distribution of the weed through time in order to illustrate the rate of spread. An initial estimate of the number of farmers to be surveyed was determined from information provided by Canada Post Corporation through its Admail ser-vice. The information consisted of lists of Saskatchewan post offices and the number of farm households served by each. Post offices in our study area were located and the number of farm households served totalled. We were constrained by our budget to surveying approximately 30,000 farmers in 1987. In 1988 we will complete the area, surveying an additional 10,000 farmers. The data was analysed using various procedures of the Statistical Analysis Systems (SAS) software package. 205 RESULTS AND DISCUSSION 1. Questionnaire survey We received 2120 usable questionnaire responses, a rate of return of 7.1%. A slight majority (35. 6%) of the farmers who responded said that the weed was present on land they farmed or on the adjacent roadsides (Table 1). Nega-tive responses were received from 34.1%. The remainder indicated that they were not sure if the weed occurred on or adjacent to their land. This group was composed of those who knew the weed but were not sure of its occurrence, and those who were not familiar enough with scentless chamomile to be able to make a positive identification .. Table 1: Presence of scentless chamomile on land farmed or on adjacent roadsides Response Present Not present Not sure Total number of responses • 2120 Number 754 723 643 Percent 35.6 34.1 30.3 Responses to year of first sighting were given by 710 farmers (Table 2). Of these, 88.0% reported first seeing the weed on their land within the last 20 years and 69.0% within the past decade. The pattern of increase through time illustrated in Table 2 conforms to that reported by Salisbury (1961) and by Forcella (1985) for introduced weed species. They discussed the phenomenon of a long period of slow increase after introduction, followed by a relatively abrupt shift to rapid expansion. The responses to the survey indicate a lag of approximately 50 years between the first report of scentless chamomile and the rapid expansion phase. Table 2: Year scentless chamomile was first sighted on land farmed or on adjacent roadsides Response Number Percent 1905 - 1917 2 0.3 1918 - 1927 5 0.7 1928 - 1937 5 0.7 1938 - 1947 8 1.1 1948 - 1957 15 2.1 1958 - 1967 50 7.0 1968 - 1977 135 19.0 1978 - 1987 490 69.0 Total number of responses = 710 206 Table 3: Most commonly reported scentless chamomile habitats Response Roadsides Farmyard and buildings Fences,lanes,powerlines Wet areas, sometimes cropped Annual crops Permanent sloughs, never cropped Pasture (seeded and native) Other habitats Total number of responses = 753 Number 523 429 335 294 226 192 188 367 Percent 69.5 57.0 44.5 39.0 30.0 25;5 25.0 48.3 The three most commonly reported habitats of scentless chamomile were road-sides, farmyards and buildings, and fences,lanes and powerlines (Table 3). These are all nonagricultural land. Numerous farmers commented that road-sides, where no active control measures are undertaken, provide a seed source for continued infestation. The fourth and fifth most common habitats, wet areas which are sometimes cropped and annual crops, are both agriculturally important areas. The reported habitats were classified into agricultural and nonagricultural land (Table 4). The agricultural land was further classified into arable and nonarable land. The arable land included annual crop, seeded pasture, peren-nial forage, wet areas sometimes cropped, winter wheat, summer fallow, fall-seeded crops and land under continuous crop. Native pasture or rangeland and hayland comprised the nonarable category. Table 4: Agricultural classification of scentless chamomile habitats Response Agricultural land Arable Nonarable Nonagricultural land Total number of responses • 753 Number 437 106 717 Percent 58.0 14.1 95.2 Almost 40% of those who rated scentless chamomile in comparison with other weeds considered it to be a significant problem or most troublesome (Table 5). The remainder felt it posed little or no problem. 207 Table 5: Comparative rating of scentless chamomile as weed problem Response Most troublesome Significant weed problem Minor weed problem Not a problem Total number of responses • 728 Number 77 210 231 210 Percent 10.6 28.8 31.7 28.8 Table 6: Association of scentless chamomile with disturbed or undisturbed habitiats Response Disturbed habitats Undisturbed habitats Total number of responses - 708 Number 492 216 Percent 69.5 30.5 Most ( 69. 5%) of those who responded associated scentless chamomile with disturbed habitats (Table 6). This is consistent with observations that scentless chamomile is an excellent colonizer of disturbed ground. Some commented that the weed was especially abundant in the ditches of newly-constructed roads. The majority (42.2%) of respondents indicated that chamomile occurred on or adjacent to 20% or less of the land they farmed (Table 7). At the opposite end of the scale, scentless chamomile occurred on or adjacent to more than 60% of the land of 20.4% of respondents. Table 7: Percent of quarter-sections farmed on which scentless chamomile occurred Response u- 20% 21% - 40% 41% - 60% 61% - 80% 81% - 100% Total number of responses • 692 Number 292 137 122 53 88 Percent 42.2 19.8 17.6 7.7 12.7 The three methods of controlling scentless chamomile most often reported were tillage, hand-weeding and herbicide use (Table 8). The high proportion reporting tillage is not surprising considering the relatively limited spec-trum of herbicides available for control. That hand-weeding was reported by an equal number of farmers is more unusual. Comments indicated that this was an option when the weed population was low, but in most cases became unfeasi-ble as the weed density increased. Some reported hand-weeding even at higher 208 weed densities because they felt it was the only method which gave effective control. This may reflect the level of concern that the farmers have for the weed, and to some extent the degree of their frustration with it. Table 8: Most commonly reported methods used for control or management of scentless chamomile Response Number Percent Tillage Hand-weeding Herbicides Swath/mow Burn Other methods Total number of responses • 508 Table 9: Most commonly reported herbicides 218 218 214 93 69 48 42.9 42.9 42.1 18.3 13.6 9.4 Response Number Percent Bromoxynil (alone or mix) Dicamba (alone or mix) Glyphosate Chlorsulfuron Clopyralid Picloram Not specified Total number of responses • 214 56 35 33 13 11 5 60 Bromoxynil herbicides, which are recommended for control chamomile seedlings, were the most commonly reported (Table 9). used by 15.4% of respondents, is often applied as a spot control. 26.2 16.4 15.4 6.1 5.1 2.3 28.0 of scentless Glyphosate, 2. Distribution of scentless chamomile on the Black and Gray soils of Saskatchewan The distribution maps are based on 1270 reported locations in a total of 379 townships. The earliest record of scentless chamomile reported in the survey was 1905 and occurred in the Stockholm-Esterhazy area. Reports of the weed from the following 20 years (Figure 1B) were confined to seven adjoining townships in the immediate area (two of the dots overlap fractional townships). The weed was reported in four more townships in this area from 1926 to 1940. It also appeared in the vicinities of Wynyard, Humboldt, Melfort, Rosthern, Glaslyn and St. Walburg (Figure lC). 209 .IURYIY AHA 1111 c=J .... m.U a. • ·-.-..-·-l 1841 TO 11155 A --. al.a 1805TO 1825 • a • • •• ... • • I 1956 TO 1970 ~ a • a. ' ' • ,,.. • s•· • • l· .. • • • I .. 1828 TO 11140 F a:l ..u:•a • • • ~ a. I "ft. • ..-: 1 :\i~l-r • • •. • • • • 1: \1.,.uo; .,r. \i\• • • ..... . . . ... . .. :.·· . . . ., ' . .. . . a· a. • .:r .. r-.:. • 1971 TO 1987 .=-t- a,. • '·· • u\i1,\1l· ·~. "\' ... :·! • .I •:\. • • • .t. l·· . ,.. . . . .. , ..... , ..... • , •• .._::iiilt! ···:=· . . r<on<• 1 scantl••• ch•oooilo oa th• Bl••• and G<aY ••••• of •••••••••••• 1190S to 19811· E•cb dot <op<•••••• a township from which there was at least one reported occurrence of scentless chamomile. The weed was not sighted in additional townships in the Stockholm-Esterhazy area between 1941 and 1955 (Figure !D). Of the other areas mentioned above, only around Wynyard was scentless chamomile reported in new townships, increasing to six the number of townships in which the weed occurred. Farmers reported seeing the weed for the first time near Annaheim, Canwood and Hafford. In the vicinities of Esterhazy, Wynyard and St. Walburg the number of town-ships from which scentless chamomile was reported increased considerably in the period 1956 to 1970. The weed was also reported from a greater number of townships located between the three centres mentioned above (Figure 1E). Townships in which first sightings have occurred within the past 17 years form an almost continuous band through the black and gray soil areas (Figure 1F). Major areas of increase were Esterhazy, Wynyard, Tisdale-Nipawin, Canwood-Shellbrook, Hafford and St. Walburg. ACKNOWLEDGEMENTS This study was made possible through funding provided under the Canada/ Saskatchewan Agreement on Agriculture Development (ERDA) for development of an integrated control program for the weed scentless chamomile. LITERATURE CITED Forcella, Frank. 1985. Spread of Kochia in the Northwestern United States. Weeds Today, 16(4): 4-6. Salisbury, Sir Edward. 1961. Weeds and Aliens. Collins, London. p.19. 211 

Distribution and rate of spread of scentless chamomile on the Black and Gray soils in Saskatchewan

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Distribution and rate of spread of scentless chamomile on the Black and Gray soils in Saskatchewan

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