6th National Cultivating Community Composting Forum Panel 5: BMPs and Rodent Control Caroline Bragdon New York City Department of Health and Mental Hygiene

1. R
a t
I p m
Preventing and Managing
Rats in Compost
Community Composting Best Management Practices
May 14, 2019

2. Outline for today
• What do rats need to survive?
• How do you Prevent rats?
• What to do when you have a rat problem
in your compost?
• What to do with the compost once rats
have been in it?

5. Harborage

6. Rat Burrow under
Compost

7. Planning for Compost
• Compost generates heat which may
attract rodents and any other vertebrates
or invertebrates
– Inspect frequently and monitor for activity
• Compost will not serve as a huge
attractant IF you only put garden and
vegetable scraps in it
– Food scraps should ONLY be introduced with
a strong rat management plan in place.

8. Pest-proofing compost
• Rodent-resistant compost bins
– All food waste should be containerized
– Containers can be solid plastic or steel, wood is easy for them to gnaw through
– Make sure the bin has a tightly fitted lid
• Using stainless steel mesh around bins
– If your bin is placed on the soil, install the mesh between the soil and the bottom
of the bin.
– Add a vertical screen (stainless steel, 6 to 8 inches into the ground) around the
perimeter of the bin.
• Managing material to prevent nesting and monitoring for
activity
• Using a raised platform with concrete, gravel fill below
• Site the compost area away from any other harborage
and keep the area clutter free

9. Rat proof compost structures
• Before installing structures:
– Dig out area that rats used to live 6” or more deep
– Lay down metal mesh/fabric that deters rats from eating through
– Fill on top of the mesh with gravel or construction filler 6” or more
– Avoid “chicken mesh” or any material that rusts

10. Rat Proofing
• Cover exterior openings within 4 feet of ground or
reachable by pipes, wires, stairs, roofs, trees, vines
• In severely infested areas – you can use poly-resin mesh
hardware cloth and embed it into the soil.
– http://www.getxcluder.com/
• Maintain screens in good repair
• Construct sewers, pipes, drains, conduits and related
openings to prevent ingress or egress of rats
• Neatly store construction materials outside the building
away from the exterior walls of the structure
• Don’t let rats nest in clutter or materials set aside for
work

11. Materials for Exclusion

12. Must cover all available
earthen space

13. Create Clean Sight Lines –
No clutter

14. Choose knock-down
methods carefully
• If you like to DIY –
you can use snap
traps.
• Trapping is for those
tough folks.
• You must check them
every day.
• You can and should
re-use your traps.
• Set traps along the
lines that rats travel.
• Make sure the trigger
side faces wall.
• Do not set traps first
couple of nights, let
them get used to your
trap.
• Use a tiny bit of bait –
not too much!

15. Rat Ice Treatment
Dry ice is the solid form of carbon
dioxide. As it melts, it turns into carbon
dioxide gas, which fills the burrow,
asphyxiating any rats inside. This method
eliminates secondary poisoning towards
birds of prey, pets, and wildlife.
Due to our successful pilot in 2016 it has
now been approved for use by the EPA in
New York State under the trade name
“Rat Ice”.

16. If you decide you need to bait
– you cannot DIY.
Work with a good pest professional:
• Must be licensed (NY Pesticide Business
Registration License) with a minimum of 5 years
experience
• Must provide labels prior to pesticide application
• Supply MSDS (material safety data sheets) and fact
sheets about pesticides
• Keeps comprehensive records of work done
• Provides a written treatment plan in advance of
applying pesticides or placing traps and bait stations
• Remember: you get what you pay for.

17. 17
Legal rodenticide use
• The label is the law
• All rodenticide labels require tamper-
resistant stations
• Read the label on both the station and the
bait
• The bait station should be secured,
locked, and labeled
• If the rodents are
inside, consider
using traps

18. Have a Professional Install Tamper-
resistant Bait Stations and Check Them
Regularly

19. Supervise your pest control
contractors
If you pay someone to treat your garden, supervise their
every move, make sure they:
• Check entire perimeter of area
• Place bait stations in likely pest areas and remove old
or unused bait stations
• Provide you information on the level of infestation
• Follow-up every 2 weeks for the first two months
following initial treatment and then inspect site once
per month
• Submit completed forms at every visit
• Provide notice when infestation has been eliminated

20. 1. Look for Active Rat Signs and Monitor the site daily
2. Have a Pest Log
3. Wash away droppings/rubmarks
4. Get rid of all clutter and weeds (weed so you can see the ground)
5. Trim under shrubs to eliminate homes for rodents, avoid dense
planting
6. Keep food waste in sealed containers
7. Use roof cement to seal cracks and holes
8. Close burrows every day
9. Cover drains with heavy-duty metal screening secured with nails
or cement
10. Install traps in paths that rats travel
Ten Things You Can Do To Prevent
Rats in Gardens

21. What are the public health concerns associated
with having rodents in a garden?
• Any animal waste can contain a wide range of potentially harmful
parasites and bacteria.
• Cats are the natural reservoir of the protozoal parasite Toxoplasma
gondii and can transiently pass it in their feces.
• Rodents can carry a range of diseases (all of
which are rarely/never reported in NYC)
– Hantavirus Pulmonary Syndrome
– Hemorrhagic Fever with Renal Syndrome
– Leptospirosis
– Plague
– Rat-bite fever
– Salmonellosis
• We have more cases of reported Leptospirosis in dogs than in
humans

22. How Dire is the Threat?
• Not dire – rodent borne disease is rarely
reported in metro New York
• Most “rat bites” reported are actually
interior mouse bites
• Good hygiene practices can prevent most
risks – wash hands thoroughly after
handling soil and wash all produce prior to
ingesting

23. THANK YOU!