苏南丘陵区秋播苜蓿苗期杂草化学控制试验

为筛选可控制苏南丘陵区一年生黑麦草(Lolium M ultiflorum Lam.)自生苗及恶性越冬杂草并对苜蓿安全的苗后除草剂,将咪草烟3个剂量水平分别与精禾草克、精稳杀得、高效盖草能各4个剂量水平进行混合于冬季施用,并分别从来年春季第一茬杂草发生情况、产量、经济效益等角度分析,得出最佳的两个混用方案:5%咪草烟水剂1.5 L/hm 2+10.8%高效盖草能0.525 L/hm 2和5%咪草烟水剂1.2 L/hm 2+10.8%高效盖草能0.375 L/hm 2。同时分析了在不同咪草烟使用剂量下一年生黑麦草发生与苜蓿产量的相关性。     

紫花苜蓿苗期除草剂筛选及防效试验

对10.8%盖草能Ec、7.5%禾阔灵Ec、5%精禾草克Ec 3种除草剂不同浓度在苜蓿田中进行药剂筛选及防效试验,结果表明,以禾本科杂草为主,宜选用盖草能,在施药量上,10.8%高效盖草能285~495mL/hm2时效果最好。7.5%禾阔灵、5%精禾草克对单子叶杂草防除效果好,对双子叶杂草禾阔灵防效明显,盖草能、精禾草克基本无效。     

春播紫花苜蓿苗期杂草的化学防治研究

紫花苜蓿(Medicago sativa L.)苗期杂草危害严重,显著影响建植,为此采用单因素完全随机区组设计的方法,探究7种除草处理对苜蓿产量、品质和杂草防除效果的影响。结果表明:2,4-DB、苯达松及其混用组合处理可有效防除阔叶类杂草,株防效在75.80%～90.65%之间;高效盖草能、精喹禾灵、烯草酮可有效防除单子叶杂草,株防效高于71.10%。喷施2,4-DB会使苜蓿的总产量减少64%以上;喷施苯达松+高效盖草能、苯达松+精喹禾灵、高效盖草均能显著地提高第2茬的产量,苜蓿总产量分别提高45.60%,45.28%和43.06%。综合考虑除草剂的安全性和除杂增产效果等方面,以苯达松+高效盖草能和苯达松+精喹禾灵2种除草处理的效果较好,可在苜蓿生产田推广利用。     

苏南丘陵区秋播苜蓿适用伴生作物筛选试验

为解决苏南丘陵区苜蓿苗期的杂草问题,从保护播种入手,在多年生黑麦草、一年生黑麦草、黑麦、小黑麦四种作物共五个品种中寻找适宜的伴生作物。通过对产量、株高、杂草率等多个指标测定分析,筛选出中新830小黑麦、赣选一号黑麦草适于用作苜蓿播种的伴生作物,同时获得两个苜蓿存活率最高的处理:苜蓿(15kg/hm2) 中新830小黑麦(150kg/hm2)撒播及苜蓿(18 kg/hm2) 中新830小黑麦(250kg/hm2)30cm条播。试验还表明撒播方式下,苜蓿播量与其竞争力不成正比。     

十四种化学除草剂对沧州地区苜蓿地杂草防效试验

选用14种除草剂对沧州地区苜蓿(Medicago sativa)地苗期的杂草进行了防除试验。对苜蓿株高,产量及杂草量的综合调查分析结果表明,高效盖草能、精禾草克、精稳杀得、拿捕净对禾本科杂草的防效为100%,苜蓿保系列各剂型在杂草株龄较大的情况下综合表现较好,其中苜蓿保2%EC将杂草率从80.6%(CK)降到了36.5%,苜蓿增产40.6%。沧州地区春播苜蓿幼苗期单独使用禾本科除草剂或阔叶草除草剂效果不理想。     

不同除草剂对苜蓿苗期光合特性的影响

为明确除草剂对苜蓿苗期安全性和光合特性的影响,采用5种除草剂设低、中、高3个浓度对苗期苜蓿的叶绿素相对含量(SPAD)、净光合速率(Pn)、蒸腾速率(Tr)、胞间CO2浓度(Ci)、气孔导度(Gs)、气孔限制值(Ls)等指标进行了测定。结果表明:5种除草剂中,乙氧氟草醚药害严重,不适合苗期使用。苯达松、高效盖草能、拿捕净和苜草净均显著降低了苜蓿的SPAD、Pn、Gs、Tr和Ls值,并随着除草剂浓度的增加而进一步降低。Ci随除草剂浓度的增加而显著升高。除草剂胁迫下苜蓿的水分利用效率提高。苯达松在苜蓿苗期安全施用的剂量为1 500mL/hm2;高效盖草能对苜蓿幼苗安全的剂量为300~450mL/hm2;拿捕净的安全剂量为1 200~1 400mL/hm2;苜草净的安全施用量为1 300~2 300mL/hm2。     

紫苜蓿优良除草剂种类及配方的筛选试验

采用室内盆栽试验方法 ,选用 6种除草剂针对紫苜蓿的抗药性进行了试验 ,结果表明 :5%豆施乐水剂 80ml/666.7m2 + 5%精克草能 60ml/666.7m2 没有药害 ;48%排草丹水剂1 0 0ml/666.7m2 + 5%精克草能 60ml/666.7m2 及各自单用虽有轻度药害 ,但对紫苜蓿的生育影响不大 ,可在生产上应用。 2 5%氟磺胺草醚水剂 80ml/666.7m2 + 5%精克草能 60ml;2 4 %克阔乐Ec40ml+ 5%精克草能 60ml;2 5%氟磺胺草醚水剂 1 2 0ml对紫苜蓿较敏感 ,不能用于紫苜蓿田除草     

化学除草剂对越冬之星苜蓿杂草防除效果的试验

为探讨研究除草剂对越冬之星苜蓿苗期的杂草防除效果,以期筛选出适宜的除草剂品种,笔者进行了化学除草剂对越冬之星苜蓿的杂草防除试验,并对苜蓿株高、产量及杂草量作了综合调查与分析。结果表明,高效盖草能、精禾草克、精稳杀得、拿捕净对禾本科杂草的防效为100％,5％苜草净在杂草株龄较大的情况下综合表现较好。苜蓿无药害的除草剂品种推荐5％苜草净在杂草株龄较大的情况下喷雾。     

苏南丘陵区秋播苜蓿适用伴生作物筛选试验

为解决苏南丘陵区苜蓿苗期的杂草问题,从保护播种入手,在多年生黑麦草、一年生黑麦草、黑麦、小黑麦四种作物共五个品种中寻找适宜的伴生作物.通过对产量、株高、杂草率等多个指标测定分析,筛选出中新830小黑麦、赣选一号黑麦草适于用作苜蓿播种的伴生作物,同时获得两个苜蓿存活率最高的处理：苜蓿（15kg/hm^2）＋中新830小黑麦（150kg/hm^2）撒播及苜蓿（18 kg/hm^2）＋中新830小黑麦（250kg/hm^2）30cm条播.试验还表明撒播方式下,苜蓿播量与其竞争力不成正比。     

几种除草剂对科尔沁沙地苜蓿杂草的防控效果

在苜蓿三个叶龄期施用除草剂研究其对苜蓿产量和杂草防控效果的影响,结果表明:咪唑乙烟酸对燕麦的防效随苜蓿叶期增加而降低,株防效和鲜重防效均为四叶期五叶期六叶期;咪唑乙烟酸和高效氟吡甲禾灵混用可以显著提高对燕麦的防效,苜蓿产量提高100～1000kg/hm2;辛酰溴苯腈与高效氟吡甲禾灵混用会降低对反枝苋的防效,但可提升对燕麦的防效,同时显著提升苜蓿产量1000～2000kg/hm2。综合考虑除草剂对苜蓿的安全性、产量以及对燕麦、反枝苋的防控效果,科尔沁沙地苜蓿苗期化学除草可在苜蓿四叶期、五叶期选用咪唑乙烟酸1200ml/hm2+高效氟吡甲禾灵660ml/hm2或咪唑乙烟酸1800ml/hm2+高效氟吡甲禾灵660ml/hm2,也可采用辛酰溴苯腈1050ml/hm2+高效氟吡甲禾灵660ml/hm2和辛酰溴苯腈1500ml/hm2+高效氟吡甲禾灵660ml/hm2。     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.

     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.