Knock, Knock. Who's There? ANTS!

When it gets hot, the ants start marching indoors. When it rains, in come the ants. Too cold? The ants know where its nice and cozy: your kitchen, bathroom and pet food bowls. Outdoors, the pet food bowls and garbage cans are also ant attractants. Argentine ants, those busy little black ants, are in march formation year round.

In years past, we would reach for the spray can and douse those little scavengers. But not anymore.

 Many of those spray pesticides are only effective with direct contact on the ants. And the stronger sprays, with residual action to thwart the next wave of ants, is potentially harmful to you, your kids, your pets.

So, here is what we are doing now: following the recommendations of the UC Davis Integrated Pest Management Project for Ant Control.

That includes:

• Determine what the ants are attracted to and remove the food source
• Vacuum trails, wipe them with soapy water, or spray with window cleaner
• Locate entry points and caulk openings or plug with petroleum jelly
• Put out bait stations with liquid ant bait or apply gel bait at entry points
• Baits take time to work so continue to clean up trails
• Indoor sprays are not usually necessary.

• Avoid products packaged as granules that contain the active ingredients cyfluthrin or permethrin. Although these products may be mistaken for baits, they are actually contact insecticides that rapidly kill foragers and do not control the colony.

Before wiping up (or wiping out) the little critters, follow their trail. Note their entry point into the house. Seal it up. We have found ants entering the house in a variety of small avenues: beneath moulding, cracks in the window frame, behind electrical outlet plates...and one of the ants' favorite entries: that large holes beneath the sink where the pipes enter the house.

According to the UC IPM page on ant control, "If ants can be thoroughly washed away and excluded from an area, an insecticide is probably not necessary. Vacuuming up ant trails or sponging or mopping them with soapy water may be as effective as an insecticide spray in temporarily removing foraging ants in a building because it removes the ant’s scent trail, especially if thorough cleaning is done at the entry points. Some soap products such as window cleaners can kill ants on contact but leave no residual toxicity. Certain plant-based oils are also applied for this purpose, but their odor can be offensive."

Oh, and another lesson we learned the hard way: if you put those ant baits indoors, you will attract more ants inside. Look for ants crawling along the outside of the house, and place the baits there, being sure to follow all label directions.

What about those ant sprays that are intended to be used as a perimeter spray along the outside of the house? Stick with the bait traps, says the UC IPM page: "Spraying around the foundation will not provide long-term control because it kills only foraging ants without killing the colony. Perimeter treatments may appear to knock down the population, but ants will quickly build back up and invade again. To try to achieve long-term control, some pest control companies offer monthly perimeter spray programs. Perimeter treatments pose more risk of environmental upset than baits in bait stations and are less effective than a bait-based IPM program."

Ant baits are not ant traps, even though some ants may be stuck there. The whole point of ant baits: they get the stuff on them, take it back to their nest, where they share it with others...and then croak. Be patient. It may take a week or so for the baits to work on the ant nest.

More info about ant baits from the UC IPM project: "Baits are insecticides mixed with materials that attract worker ants looking for food. They are a key tool for managing ants and the only type of insecticide recommended in most situations.  Ants are attracted to the bait and recruit other workers to it. Workers carry small portions of the bait back to the nest where it is transferred mouth-to-mouth to other workers, larvae, and queens and other reproductive forms to kill the entire colony. Bait products must be slow-acting so that the foraging ants have time to make their way back to the nest and feed other members of the colony before they are killed. When properly used, baits are more effective and safer than sprays." 

• Sweet sugar baits such as boric acid (use low concentrations with less than 1% of the active ingredient) are highly attractive to Argentine ants throughout the year. 

 

• Protein baits are attractive to ants in spring when colonies are producing new offspring. (Baits like fipronil or hydramethylnon are effective.) 
• Place baits outdoors; avoid indoor baiting as that may attract more ants into the home. 

• When using liquid ant baits outdoors, there are reusable ant bait stations available that hold the liquid, such as the Ants No More Ant Bait Station.

 

• Place baits near nests, trails, or along foundations, preferably in the shade. 
• Baits should be placed in protected areas away from children and pets. 
• Offer small portions of each bait to see which one is preferred before employing an extensive baiting program. 
• Follow up regularly to make sure bait is working and place fresh bait as necessary. 
How baits work:
• Worker ants are attracted to the bait and take it back to the nest where the entire colony, including queens, may be killed. 
• Bait must be slow-acting so workers won't be killed before they get back to the nest. 
• Results may not be evident for several weeks. 
• Bait stations or ant stakes are easiest to use and safest for the environment.

Ant baits contain various active ingredients and attractants. We have tried a variety of different ones, to appease the finickiest of ant diners. Besides the Gourmet liquid ant bait, another one of my favorites is powdered boric acid in a squeeze bottle, another less toxic alternative.

For those that prefer a homemade concoction for ant control, Horticulture consultant Debbie Flower of Sacramento recommends this formula:

1 part boric acid (I use 1 teaspoon) - available at most garden centers

9 or 10 parts sugar (so 9 or 10 teaspoons sugar)

Add enough water to make a slurry.

Put slurry in a small container, tuna can size.

Add 2 or 3 cotton balls and rotate them until they are completely covered in the slurry.

Put a lid on the container.  Lid must have holes big enough for ants to crawl through.  (Lid is not absolutely necessary but it keeps water and dirt out)

Bury in soil so lid is at soil level.

Leave it alone.  You won't see dead ants.  They visit, take the bait back to the colony, and kill the entire colony.

Ants in Your Worm Bin? Here's a Solution.

I can't recall where I read this solution to ants in a worm composting bin, but it works! 

Put water-filled coffee cans on each of the legs (if your bins have legs, such as this worm bin). Ants can't cross the water. For ants roaming on the outside of the container, wipe them away with a glass cleaning spray. The white ant baits at the base contain boric acid, which the ants take back to their nest. In a couple of weeks, no more ants living with the worms! P.S. Make sure no weeds are touching the base of the bin, because they'll use that as their ant freeway! (Yes, this lesson was learned the hard way.)

Controlling Sooty Mold

From the garden email bag, Gus from Lodi wants to know: “We have a great crop of oranges now despite the fact that many of the fruit and leaves are coated with a black substance that is easily washed off of the fruit. The fruit tastes great. Can you help? Thanks.”
 

 

That substance may be sooty mold, which is a fungus that results from the excrement of sucking insects such as aphids or scale.

 

According to the UC Davis Integrated Pest Management experts, sooty molds do not infect plants but grow on surfaces where those excrement deposits accumulate. This excrement, also known as honeydew, is a sweet, sticky liquid that plant-sucking insects excrete as they ingest large quantities of sap from a plant. Because the insect cannot completely utilize all the nutrients in this large volume of fluid, it assimilates what it needs and excretes the rest as honeydew. Wherever honeydew lands - leaves, twigs, fruit, yard furniture, concrete, sidewalks, or statuary - sooty molds can become established.

Although sooty molds do not infect plants, they can indirectly damage the plant by coating the leaves to the point that it reduces or inhibits sunlight penetration. Without adequate sunlight, the plant’s ability to carry on photosynthesis is reduced, which can stunt plant growth. Coated leaves also might prematurely age and die, causing premature leaf drop.
 

And as you pleasantly discovered, fruits or vegetables covered with sooty molds are edible. Simply remove the mold with a solution of mild soap and warm water.

To thwart any new outbreaks of sooty mold, do not overprune, overfertilize or overwater your pest-prone plants, says the University of Florida Ag Service. These bad habits can create weak, succulent new growth on the plants, a delicacy for sucking insects.

Beginning of sooty mold. Note the small white mass of scale on the stem.

To control sooty mold, you have to control the pests. On citrus, soft scales, such as cottony cushion scales, are the usual culprits. This scale can be controlled with a light horticultural oil when the scale are in their crawling stage.

Cottony cushion scale on mandarin branch

Sooty mold can attack any plant that may have an infestation of other sucking insects, especially aphids, leafhoppers, psyllids, and mealybugs.

The UCD IPM pros also advise against using insecticides containing the active ingredient imidacloprid for controlling this pest. Although scale is listed on the label as a pest that it can control, it is not effective against cottony cushion scale. 

Photo courtesy UC IPM

 To complicate matters, imidacloprid will reduce populations of the beneficial insect, the vedalia beetle. Both the adults and larvae of the Vedalia beetle feed exclusively on the cottony cushion scale on a variety of plants including rose, acacia, magnolia, olive, and citrus.

One product that can help control many of these pests, while washing off the sooty mold from leaves or fruit, is insecticidal soap. Even a blast of water from the hose can help wash off the sooty mold without harming any beneficial insects that might be trying to help you out. Horticultural oils or Neem oil can also suppress scale populations.

Also, look for ants crawling up and down the tree. Control the ants, and you can control the pests...as well as the sooty mold. Ants herd and protect sucking insects from beneficial insects, in order to harvest the honeydew for the ant colony.

Baits containing boric acid placed around the base of the tree will control ant populations in a couple of weeks. Sticky substances, such as Tanglefoot, although messy, can stop ants. See this previous post on ant control.

 

For plastic or painted surfaces that might have sooty mold, the USDA recommends this cleaning solution:

1/3 cup powdered household detergent 

1 quart household liquid bleach

2/3 of a cup of Trisodium phosphate

3 quarts of water. 

Be sure to wear rubber gloves when cleaning with this solution.

Ants!

     I had plans to rant about a number of personal vexations this week:

• Stores (usually supermarkets and big box stores) that sell cool-season annuals alongside warm-season annuals this time of year; 

• Advertising campaigns for pesticides that claim their products are "natural", "lawn friendly", "environmentally friendly" and "safe to use"...when none of those things are true, after reading the label;

• Weed whacker maintenance.

Instead, taking priority, is...ANTS!

The spring indoor migration has begun. Argentine ants, those busy little black ants, are march, march, marching through the kitchen and bathroom.

In years past, we would reach for the spray can and douse those little scavengers. But not anymore.

 Many of those indoor spray pesticides are only effective with direct contact on the ants. And the stronger sprays, with residual action to thwart the next wave of ants, is potentially harmful to you, your kids, your pets.

So, here is what we are doing in 2010: following the recommendations of the UC Davis Integrated Pest Management Project for Ant Control.

That includes:

• Determine what the ants are attracted to and remove the food source
• Vacuum trails, wipe them with soapy water, or spray with window cleaner
• Locate entry points and caulk openings or plug with petroleum jelly
• Put out bait stations or apply gel bait at entry points
• Baits take time to work so continue to clean up trails
• Indoor sprays are not usually necessary.

• Avoid products packaged as granules that contain the active ingredients cyfluthrin or permethrin. Although these products may be mistaken for baits, they are actually contact insecticides that rapidly kill foragers and do not control the colony.

Before wiping up (or wiping out) the little critters, follow their trail. Note their entry point into the house. Seal it up. We have found ants entering the house in a variety of small avenues: beneath moulding, cracks in the window frame, behind electrical outlet plates...and one of the ants' favorite entries: that large holes beneath the sink where the pipes enter the house.

According to the UCD IPM page on ant control, "If ants can be thoroughly washed away and excluded from an area, an insecticide is probably not necessary. Vacuuming up ant trails or sponging or mopping them with soapy water may be as effective as an insecticide spray in temporarily removing foraging ants in a building because it removes the ant’s scent trail, especially if thorough cleaning is done at the entry points. Some soap products such as window cleaners can kill ants on contact but leave no residual toxicity. Certain plant-based oils are also applied for this purpose, but their odor can be offensive."

Oh, and another lesson we learned the hard way: if you put those ant baits indoors, you will attract more ants inside. Look for ants crawling along the outside of the house, and place the baits there, being sure to follow all label directions.

What about those ant sprays that are intended to be used as a perimeter spray along the outside of the house? Stick with the bait traps, says the UCD IPM page: "Spraying around the foundation will not provide long-term control because it kills only foraging ants without killing the colony. Perimeter treatments may appear to knock down the population, but ants will quickly build back up and invade again. To try to achieve long-term control, some pest control companies offer monthly perimeter spray programs. Perimeter treatments pose more risk of environmental upset than baits in bait stations and are less effective than a bait-based IPM program."

Ant baits are not ant traps, even though it may look like they are stuck there. The whole point of ant baits: they get the stuff on them, take it back to their nest, where they share it with others...and then croak. Be patient. It may take a week or so for the baits to work on the ant nest.

More info about ant baits from the UCD IPM project: "Baits are insecticides mixed with materials that attract worker ants looking for food. They are a key tool for managing ants and the only type of insecticide recommended in most situations. Ants are attracted to the bait and recruit other workers to it. Workers carry small portions of the bait back to the nest where it is transferred mouth-to-mouth to other workers, larvae, and queens and other reproductive forms to kill the entire colony. Bait products must be slow-acting so that the foraging ants have time to make their way back to the nest and feed other members of the colony before they are killed. When properly used, baits are more effective and safer than sprays.

• Sweet sugar baits such as boric acid (use low concentrations with less than 1% of the active ingredient) are highly attractive to Argentine ants throughout the year.

• Protein baits are attractive to ants in spring when colonies are producing new offspring. (Baits like fipronil or hydramethylnon are effective.)

• Place baits in late spring or early summer when populations are low.

• Place baits outdoors; avoid indoor baiting as that may attract more ants into the home.

• Place baits near nests, trails, or along foundations.

• Baits should be placed in protected areas away from children and pets.

• Offer small portions of each bait to see which one is preferred before employing an extensive baiting program.

• Follow up regularly to make sure bait is working and place fresh bait as necessary.

How baits work:
• Worker ants are attracted to the bait and take it back to the nest where the entire colony, including queens, may be killed.

• Bait must be slow-acting so workers won't be killed before they get back to the nest.

• Results may not be evident for several weeks.

• Bait stations or ant stakes are easiest to use and safest for the environment."

Ant baits contain various active ingredients and attractants. We have tried a variety of different ones, to appease the finickiest of ant diners. One of my favorites is one that uses boric acid, a less toxic alternative.

But again, use it outdoors...otherwise, you will be drawing more ants inside.