To control powdery mildew and other fungi, use a mix of powered milk in water. Spray both under and top sides of leaves. So far I have found this to be a very useful solution for fungus on tomato plants, chile plants, cucumber and squash plants! I use about a 50 percent milk solution. I have had no problems with the leaves burning. Leaves already infected generally still die back, but the newer leaves are staying healthy.

Alternative method:
To control powdery mildew and other similar fungi, use 1 tsp baking soda in 1 quart of water and spritz the leaves top and bottom. Spray leaves at first sign of the mildew. As the name implies, powdery mildew looks like a fine layer of white or a water spot–white halo spots on leaves. Crepe Myrtle gets powdery mildew in Texas quite often. I spray when the myrtles begin showing leaves in the spring. Snap peas and snow peas also have this problem when the temperature hits about 78. Again, you’ll have the best luck if you spray early.

Because Baking soda isn’t good for the soil, do not overspray. The baking soda changes the pH on the leaves and inhibits the growth of mildews.

I often put a tsp of soap in with the baking soda–the soap works as an insecticide for soft bodied bugs (aphids, some stages of thripes, etc). Use liquid hand soap–not dishwashing soap or detergents.

Tomatoes and other plants can also get a mildew although it is a different type. The leaves turn yellow from the bottom of the plant up. Little brown circles are often on the yellow leaves. The fruit will continue and be unharmed, but a spritz of the milk solution (or baking soda) can help. Note that some bugs such as spider mites will cause yellowing of the leaves from the bottom up.

Update Some recommendations advise using milk one week and baking soda the next. Thus far, I’m having better luck with the milk–it doesn’t burn the plants in 90 degree weather and seems to work better. The baking soda solution works also and has the added benefit of killing bugs when I put soap in the mix–however I have had some leaves burn pretty badly. I read that the milk solution works best against the mildew during sunny days because something in the ultraviolet gets the action started that kills the mildew. A similar milk solution with flour added is rumored to kill spider mites. I’m hoping that the milk alone might kill them also as spider mites are always trying to get a hold on my garden!

Update 2009:  Since I’m already using neem oil for spider mites on things like snap peas and tomatoes, I’m going to see how well it does to control the mildew without trying the milk.  It’s been a dry winter–that may help all on its own, but at any rate, the neem is supposed to be helpful against mold and mildew so we will see how it goes!

Finally the tomatoes are turning! Getting about two a week. Hoping the juliets (large grape) will start turning faster. I kinda need more than two of those to make a salad…

Neem oil versus milk for mildew/fungus: I think the milk wins. Both seem to help, but the milk seems more effective. When I was only using neem oil, I still saw mildew to such a large degree on the snap peas, I think it could have overtaken and killed the plant. The mildew was probably caused by cloudy/wet weather we had, as well as possibly spread by no-see-ums. They were flocking about.

Remember that you need sunlight (according to studies) for milk to work. I spray after it rains and have been combining it with the neem oil. I use the milk at about half strength (mixed from the dry powder.) I think the milk worked better on the rosebush spots too.

Neem oil has been fairly effective against spider mites. That is to say it is keeping them under control. It hasn’t eliminated them completely, but I’m not sure a nuclear bomb could do that. I spray in the evenings when a few cooler days are expected. I am very careful not to use more than the recommended mix because it can and does burn the leaves (both my snap peas and tomatoes got burned when I wasn’t measuring very carefully). Using less than the recommended mix, doesn’t seem to get the mites. Mites are stubborn and way too hardy.

Neem is very effective against aphids. Not sure about thripes yet, but I’m trying. The thripes get into the blossoms of tomato, cucumber and other melons. Whenever they are around, the fruit seems to have a hard time setting (doesn’t set at all or the fruit is small and/or deformed.) I think I have less thripes around than last year, but none of the melons or cucs have set yet. Ants are a huge problem because the minute I kill off the aphids and thripes, the ants bring more into the garden to harvest the “dew” from these insects. I hate ants almost as much as the thripes.

There is also a lack of bees in the garden–a bit unusual since I had a gazillion earlier. There was a late freeze which might have affected them. I’m told the neem oil is perfectly safe for bees and never spray them directly at any rate. Of course when bug season starts around here, there are many other gardeners spraying more lethal ingredients than I use.

I kill things with my bare hands quite often, but I have got to tell you, there is something…evil about tomato horn worms. For one, they are HUGE. Seriously. These things can get longer than my fingers and strip an entire branch of leaves in one night. Worse, they have these claw appendages that cling to the plant when you try to knock them off. I defy you to just brush them off a plant. It can’t be done. Maybe they have suction cups under their big, fat green bodies. I’m not going to look.

All I know is that when I spot one–and it’s usually because I notice a sudden lack of leaves on a part of the plant–I do NOT want it clinging to my hand or arm if I yank it off with my fingers. Uh-uh, no way. Gloves. And not those cute little cotton gardening gloves with flowers on them either. Leather. Like for roping or branding cattle.

Of course, you can use Green Light 27316 1-Pint Organic BT Worm Killer on these guys, but with as fast as they eat, when I do spot them, I’ve no real choice but to remove them and step on them. With special shoes that do not get worn into the house. I mean, do I want green goo on my carpet?

Ish.

(photo stolen from the K-State website, no direct credit was listed)

The Neem Oil is working against the spider mites and aphids, but I do have to spray weekly. I was sooo hoping to find something safe that didn’t require constant upkeep. It’s now, when it’s 95 every day, that I’m thankful I didn’t plant so many tomato plants. No, I’m not getting as many big fat tomatoes–barely enough for us, but when I have to go out in the evenings to spray when it is still pushing 91, I am just happy to get done inside an hour. I think the neighbors are going to be disappointed this year. Yields aren’t high enough for sharing. Maybe there will be enough cucumbers. I picked two yesterday and there are another three coming in.

I do have one watermelon forming. It’s small yet so don’t be counting my watermelons before they are larger than a quarter!!! There’s a just-bigger-than-a-golf-ball cantaloupe out there too. No sprite melons. I haven’t even seen anything but male blossoms. The plant is beautiful though. Nice and green and creeping all over the garden.

The chili plants had a few beetles chewing on them. The snap pea plants are almost completely dead except near the very top. Disappointing yields on those and I planted them five or six times. A bird ate all my blueberries. Sometimes you get fruits, sometimes you get work without the yield. I’ll have to instruct those cats to watch the blueberry bush more carefully (like AT ALL.) The cats have been doing their job where the tomatoes are concerned. Different bird, different time of day.

Not to worry. I’m focused on those melons even though I’m not counting on them.

If I sold my organic veggies, I’d charge a fortune.

The tomato plants have not been making their usual comeback. I suspected any number of varmits, creatures, bugs, diseases…but no, tomato horn worms was the winner. Now that the bugs are down in numbers due to cooler nights (and seasonality) the horn worms apparently decided to move in for the final kill.

If you’ve never had the dubious pleasure of dealing with a tomato horn worm, let me take this opportunity to bring you into the fold. Tomato horn worms can strip a plant of leaves and blossoms in under a week–a full grown plant. They run from starter size–about 1/2 long and 1/4 inch around–to the size of a pro basketball player’s shoe. Okay, maybe slightly smaller. But I swear I picked one off this morning that was the size of *my* shoe, and I do not have small feet. Is there *anything* grosser than having to stomp on a worm full of digested plant juice? Seriously, we are talking grosser than gross. You have to smash carefully because you do *not* want the thing to squirt all over you. So you sort of roll it under your shoe, mushing it down to a…well, a rather giant green smear about the size of your shoe.

And that’s after you pry these fat, disgusting suckers off with either a crowbar (my weapon of choice) or pliers. Pliers work, but if the worm is big, it might touch you. And if it touches you, it will grab onto your hand with the suction and claws of a leech on steroids. It is *most* unpleasant.

Yes, there is an organic worm killer (Green Light 27316 1-Pint Organic BT Worm Killer. Kills only leaf eating worms.) Of course, I’ll be spraying that tomorrow morning when it is cool out. The problem is that the worm has to eat a few of the leaves before the worm feels ‘full’ and stops eating–forever. Meanwhile, my poor remaining tomato plant will suffer some additional damage.

Darn worms.

I had fearsome slug problems in Houston. The slug bait works well—but it kills birds. I had several dead baby birds (they tend to be feeding on the ground during their “learning to fly” stage.) They eat the bait because the poison is hidden in grain.

Best solution is to put the slug bait in a plastic bottle (soda type bottle). Put the lid on, and cut a hole (slug door) in the side of the bottle about half way down. Bury the bottle up to the slug door. The slugs will crawl in and eat the bait. The birds will not.

Dispose of the whole bottle when a few slugs have made it their graveyard.

Note: Beer does not kill slugs. They are attracted to the beer, and they probably drink it. They also swim around in it and out the other side because I’ve watched them do this. A deeper container just seemed to make their stay last longer. I never actually saw any of them drown.

Second Note: Don’t use salt. It does kill slugs, but it ruins the soil for all other things you are trying to grow. Slugs weren’t much of a problem in the hill country, but I haven’t tried growing strawberries yet, a favorite food of slugs!

All you Texas gardeners, the first spider mites have been sighted! Time to get out the neem oil and spritz the underside of leaves before they web the plants and suck all the juice out of the leaves!

What are spider mites? Tiny little insects (not actual spiders–oh that they were!) These nasty beasts eat the sap of leaves and multiply very, very quickly, generally destroying one plant at a time in the garden. This year (in Austin) like last year, the variety that is in my garden is a red spider mite. The red spider mite looks like tiny red dot on the underside of snow peas, snap peas, tomato plants, raspberries, juniper trees, etc. If you see webbing near the top of a young juniper tree later in the season–where there is new growth, it’s usually spider mites. The juniper trees can generally handle the mites unless it’s a very dry year when the mites can kill the tree.

How to spot them? You can see them with the naked eye if you know what to look for, but they are difficult to see. They are generally near the bottom of the plants–lower leaves. The lower leaves may be starting to yellow. If there are eggs, this looks like a smattering of dust tucked under the leaves–very light brownish/beige dust. There may be what looks like a tiny web across the back of such leaves. The mites themselves can be beige, brown, red, or brown with a couple of spots (you won’t see any spots unless you’re using a magnifying glass). Some people say you can put a white sheet of paper under a leaf or two and tap on the leaf and see if mites fall off. I think the suckers cling to the leaves, so you’re better off looking for yellow spots and webbing on the leaves or using a magnifying glass to inspect the lower leaves.

What to do? Neem Oil works well against these pests, but it takes several applications.  Spray EARLY–I would advise you spray before you see the mites.  Neem oil works as a deterrent and with spider mites, you need all the help you can get.  If you see mites, spray directly–along with the whole plant.   If it is cool out (70s) I spray every 3 to 7 days.  You’ll need to repeat in 7 days and again in 7 days. I generally do a day, wait three, wait 4, then wait 7.  Neem oil can stunt photosynthesis for a day or so–when using on very young plants (3 to 8 leaves) don’t spray more than once a week. I noticed this most with cucumbers and melons. Rub off the spider mites or other pests inbetween spray cycles if you see them.

You can also try insecticidal soap (1 Tbp liquid hand soap to 1/2 gallon of water) which kills immediately, but does nothing against the eggs. 

Neem oil takes a few days to kill the mites and eggs.  In fact, it appears to be doing nothing for about the first 3 days, but take heart; it will work and in the end is longer lasting than chemical sprays–very few of which actually work against spider mites and thripes.

Neem oil can burn the plant if it is too hot out. I’ve found that I can spray as long as it is under 90. After that, you risk burning the leaves. I have sprayed in the evening and then rinsed the plants in the morning (if the day is going to be 90 plus, I’ve had damage that likely came from the neem oil up to three days after spraying). Rinsing is tedious, but the neem oil works a lot better against mites and thripes than anything I’ve tried so that is the method I’ll be trying this summer (2009).

You can look for an insecticide that is specifically for spider mites. Some of the broader, general sprays don’t work very well against them. Mites are hard to control–but if you start early, you’ll have a better garden!!!

I’m not big on spraying for pests and try to be organic. A few things I did learn—spider mites are prevalent in both Houston and the hill country—and most organic solutions and generic sprays including pyrethrins and malathion sprays didn’t do much against them. I even tried getting natural predators shipped to me. The predators either died because of the heat or left because of it, and the spider mites multiplied faster than a barnyard full of rabbits.

Find a spray specifically for spider mites. Most plant nurseries carry the specific insecticide—Home Depot type places did not. The spider mite spray worked very well—it was from Greenlight. I say was, because it is no longer available. If you can find something specific to just spider mites it will probably work well—spray before you see serious signs of mites. I’m using Neem Oil at the moment (also from Greenlight and I think Garden Safe also makes a neem oil product).

If you have a juniper tree (this includes cedar) dying from what looks like drought, it’s probably spider mites. Neem oil works on spider mites, but is a contact spray so you must spray 7 days apart to keep infestations down. Also, if you have had mites in the past, spray before you see any mite damage.

In some ways insecticidal soap works faster than neem oil, but does nothing against eggs and is not a deterrant. Both pesticides have to be sprayed 7 days apart (or sooner) and you have to keep after them constantly. After trying both, I think the neem worked better, but I was spraying it more often than seven days apart. Also, any pesiticide should be used before it is too hot, including neem oil–it can burn the leaves.  So spray early while it is in the 70s and spray often.  As it gets into the 80s cut back and do the spraying in the evening.  I’m not certain you can use neem oil once the temps are above 90.

I’ve also had infestations of thripes—Sevin dust seems to work well but below I’ve described a few things that I tried that also worked. Some of them were more work to apply. Lots more work in some cases.

Update 2009:  I’m going with the neem oil this year.  I’m using it for spider mites anyway and it does seem to work on thripes.  I’ve also put off planting chile plants for the second year in a row–thripes thrive on them and I’m hoping that if I take a couple of years off maybe I can get the bug numbers down enough to make a difference.  The sevin last year did seem to help a lot, but this year, I don’t think I need it–at least not yet.  So far the neem seems to be doing the job so I’ll keep at it.

2008 updates:

Neem oil (or insecticidal soap instead of the neem oil)–Neither product is harmful to humans, fish, lizards or anything except bugs. Using the spray seemed to kill and discourage ants, thripes and aphids. I tried diatomaceous earth but it didn’t bother ants at all and killed little else except for maybe the aphids. It is tedious to use because you have to reapply after every rain and sometimes more often, depending on your watering methods. I used a basting brush to apply the diatomaceous earth on the undersides of leaves, but if your garden is large, this could be beyond tedious and frankly, I don’t think it killed enough to be worth the effort. Ants laughed and crawled right across the stuff and I saw no effect on thripes either. It may have killed some nightworms that were eating my tomato plant leaves

Most insecticidal sprays don’t get rid of thripes because they spend a lot of time down in the soil. The sprays will kill the ones out on the plant, but the majority are in hiding and they will just keep coming out and attacking when you aren’t looking, so you will have to spray once a week and early in the season to keep this bug from getting out of hand.

Bad Thripe Infestation—A malathion spray killed whatever it hit, but it wasn’t killing anything by the next day–more bugs were back and the population seemed to be growing rapidly. I finally settled on insecticidal soap for seven days in a row. I actually bought the Safer brand, but you can also use two to five tablespoons of liquid Dial in a gallon of water (I used that in Houston—the amount of soap depends on what you are trying to kill).

The soap killed everything on the plant on contact, but it took about 5 to 7 days before the number of bugs died down to zero. This product is generally pretty friendly to the environment, but can “burn” the plants if overused or if used during the hot part of the year. I try to get control of the bugs before the temperatures hit 90—after that I have to be very careful if I spray insecticides at all.

For the first two days, I was spraying first thing in the morning and again in the evening. The bugs were so bad that the blossoms were half eaten and none of the chiles were setting. By the third and fourth day I was spraying only in the evenings and most of the bugs were gone, but I could still see thripes hiding in the blossoms. By day seven, I was spotting no bugs and the chiles were setting rather than dropping off. Usually once the bug population is under control I don’t have too many problems.