Presentation is loading. Please wait.

Presentation is loading. Please wait.

Heath Sanders Area Extension Agronomy Specialist March 20, 2019

Similar presentations


Presentation on theme: "Heath Sanders Area Extension Agronomy Specialist March 20, 2019"— Presentation transcript:

1 Heath Sanders Area Extension Agronomy Specialist March 20, 2019
Coffee Shop Talk Heath Sanders Area Extension Agronomy Specialist March 20, 2019

2 180-Day Rainfall

3 Discussion/Updates Pasture Weeds Musk Thistle, Prairie Threeawn,

4 Causes for Weeds in Pastures
Poor stand of adapted forage Inadequate fertility Improper harvesting Overgrazing DROUGHT Soils and climate Invasive weeds There are a number of causes for weeds in pastures but usually the root of the problem is overgrazing or poor harvest management. This year a drought in the southern portion of the state caused the overgrazing that will end in a heavier than usual weed population this spring. Overgrazing leaves less residue which means less weed suppression due to shading when the annual weeds are germinating in the spring. Musk Thistle is an example of an invasive weed.

5 Thistles in Oklahoma Native-not a major threat Introduced “Invasive”
Wavyleaf Yellowspine Tall Yellow Introduced “Invasive” Bull Musk Scotch Distaff Canada

6 Musk Thistle - Recognizing The Plant
Unique Characteristic - Does not have hair (pubescence) between the spines. I.E., smooth leaves and stems. Leaf margins often silvery Bull Musk Scotch

7 Musk Thistle Biennial - 2 years to mature or can act like an annual in OK. Germinate in fall Overwinter as rosette Bolt and produce seed in the spring Deep rose to violet or purple in color Aggressive Germinate Anytime 10,000-20,000 Seed Per Plant Continuing to germinate for 5 years Livestock Do Not Graze Infested Areas

8 Integrated Management Approach for Musk Thistles
Prevention Mechanical Chemical Biological

9 Prevention Thistles spread by movement of seed-contaminated Hay Wind
Water

10 Prevention Do not allow thistles to produce seed
If present, avoid the use of hay and feed from infested areas Destroy plants before they produce seed

11 Mechanical Control Some flowers can still produce seed
Tillage or Mowing Cut Below The Crown Spade or Garden Hoe Mow to suppress seedhead production Close to the ground as possible Some flowers can still produce seed

12 Chemical Control Good moisture Actively growing 60o F + temperature
Before seedheads are mature. Always read and follow the herbicide label

13 Chemical Control Fall (Oct. and Nov.) Spring (Mar. - April)
Applications to rosette plants Before plant starts bolting Spot treatments

14 Chemical Control 2,4-D, Weedmaster 2 pt./A Grazon P+D
2-4 pt/ac Weedmaster 2 pt./A Rosette-Bolt Grazon P+D 2 pt/ac rosette 3-4pt/ac late season, bolting-bud Cimarron Max rate I Pasturegard 3 pt./A GrazonNext 1.5/2 pts/ac Always read and follow herbicide labels

15 Biological Control The use of natural enemies to reduce populations once area is infested Thistle head weevil and rosette weevil Advantages Low cost Non-target organisms are unaffected Adjoining infested areas will attract the control agent Requires little effort once established Can be used with other methods

16 Biological Control Head weevil – lays eggs on the bracts of newly emerged flower heads When eggs hatch, larva make their way to the young seed of the head Feed and destroy musk thistle seed Head weevil

17 Biological Control Rosette weevil –smaller than head weevil
Feeding of the rosette weevil can lead to less competitive multiple stemmed plants, that produce seed or destruction of the growing point Rosette weevil

18 “Weevil Roundup” 1-2 per year in Oklahoma
Alfalfa Co. Okfuskee Co. Both head and rosette weevils are collected From bolted plants Take and release them Within 48 hours

19 Prairie Threeawn

20 Prairie Threeawn Other names Annual short grass
“Old-field threeawn”, “ticklegrass”, “wiregrass” Annual short grass Can establish easy under adverse conditions Undesirable forage, unpalatable, difficult to chew, very low quality, seeds can cause eye problems Referred to as a “indicator” grass On range sites that are heavily eroded, routinely overgrazed, or lacking nutrients

21 Fertility Critical lacking nutrient is (P) Phosphorus
(DAP) 100lb/ac of DAP in most cases will meet P needs for the year and possibly start building some residual Manures, chicken litter have sources of P too Bermudagrass pasture- recommend fertilizing according to soil test Encourage Bermuda stands to thicken and cover

22 Fertility Native Pastures
Don’t usually recommend fertilizing but, in this situation get a soil test Apply some P if needed Graze instead of haying Use lighter stocking rates Allow for rest period later in growing season Feed hay or put troughs out in the worst three awn areas in the winter Will take time to recover, didn’t happen overnight

23 Prescribed Fire Fall fire before December has proven to be effective
This is essentially destroying the seed before they reach the soil Fire Timing Threeawn Perennial Grasses Western Ragweed Unburned 74% 21% 5% Spring (4/27) 84% 14% 2% Fall (11/8) 76% 7% This Prairie Threeawn (PTA) study by Kstate occurred over 5 years on multiple native sites. The average PTA infestation was ~75%. The use of a spring fire encouraged the increase of PTA density and as such is not recommended when PTA is dominate in the landscape. However, they found that a fall burn, after killing frost but before December drastically reduced the prevalence of PTA in following years. The researchers noted this is due to the nature of PTA holding its seeds until approximately December, where the fire is able to fully consume most seeds produced in the current year. Fall fire in November! Study conducted by Kansas State University ( ).

24 Chemical Control No good herbicide options labeled for the control of threeawn Glyphosate, (non-specific) can be applied at 8 oz/ac in bermudgrass field but not native pastures. No labeled herbicide in native pastures

25 Private Applicator Certification
Required for use of Restricted Use Pesticides on owned or leased farms New packets available at the county Extension office Current Cycle expires 12/31/2018 Next Cycle will expire 12/31/2023 Open Book Test CEU’s not applicable

26 Questions?


Download ppt "Heath Sanders Area Extension Agronomy Specialist March 20, 2019"

Similar presentations


Ads by Google