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Integrated Pest Management Really Works

Pesticides are effective but innately toxic.

Wildlife is not the only menace to home garden fruits, nuts and flowers. All sorts of insect pathogens want their share also. Old fashioned nonselective insecticides can be helpful, but can leave toxic residue. They also eliminate beneficial insects that might help control pathogens. Integrated pest management, or simply IPM, is likely a more practical option.

Integrated pest management involves biological, cultural and physical pathogen control. Biological control can involve introduction of beneficial insects that consume pathogens. Ladybugs or lacewings are available from certain nurseries, for control of certain insects. However, doing nothing but allowing beneficial insects to proliferate naturally may work.

Some types of integrated pest management are standard procedure for home gardening. Cultural control may be as simple as growing varieties that are resistant to certain pests. This also involves not growing varieties that are susceptible to locally problematic pests. Sanitation is merely removal of detritus that some pathogens proliferate or overwinter in.

Physical or mechanical integrated pest management can be as simple as picking snails. Copper tape as a barrier to exclude snails and slugs is more involved but more effective. Sticky barriers, like ‘Tanglefoot’, prevent ants from cultivating aphid. (Ants cultivate aphid for sustenance.) Then, wasps, which are a biological control, control the aphid naturally.

Integrated pest management also includes various insect traps. Wasp traps use bait, like pheromones or sweet aroma, to attract stinging insects. Although they are not a problem for vegetation, stinging insects complicate gardening. Thrip traps attract thrip with yellow color, and trap them in glue. Apple maggot traps resemble developing apples, with glue.

Chemical pesticides are not beyond the realm of integrated pest management. However, such pesticides should be as nontoxic as possible. Furthermore, they should target only very specific pathogens. Although modern pesticides are safer than old fashioned types, they are still poison. They have significant potential to interfere with natural ecosystems.

Posted on by tonytomeo · 7 Comments

Aphids

Aphid enjoy fresh new growth of roses.

Since the seeds arrived in the mail from Renee’s Garden, I have been waiting for the pale yellowish white ‘Buttercream’ nasturtiums to bloom. The appearance of their first few leaves was quite an event. They then started to grow a bit faster like annuals do this time of year. Then, suddenly and without warning, they where overtaken by a herd of hungry aphids!

These small but prolific insects congregate at the tips of new foliage and flower buds. They pierce fresh tissue and suck out the juices within. They are more often yellowish green, but can be grayish black, pale white or sickly pink. Although minute, the fattest aphids can be as plump as caviar.

Fortunately, aphid are typically not problematic for very long, and are easier to control than other insect pests. Even without insecticides, their festivities will be brief before their natural predators move in and break up the party. Pesticides can actually be detrimental by also killing some of the natural predators, and delaying their conquest of the aphids.

Right now though, I do not care! The aphids are hurting the nasturtiums. They must die!

On tougher plants like roses, aphids can be blasted off with water from a hose. Because roses can get mildew if their foliage stays wet too long, they should get blasted early in the day, so that they can dry in the sun. This procedure does not kill all the aphids, and may not even dislodge all of them, but it slows their proliferation so that the natural predators have the advantage.

Nasturtiums and other annuals that are too soft to get blasted with water can instead be sprayed gently with very slightly soapy water, which efficiently kills aphids. Water with a bit of vinegar, or a ‘tea’ made from cigarette butts, also work. Foliage is less likely to be damaged if rinsed afterward. This likewise does not kill all aphids, but controls them long enough for the predators to take over.

Parasitic wasps, syrphid flies, lacewings, lady beetles and predatory midges all eat aphids. They only need some time to do so because they rely on the primary proliferation of aphids to feed their own proliferation. In other words, there must be enough aphids to feed the predators before there can be enough predators to feed on the aphids.

However, aphids have an ally. Ants dutifully protect aphids from their predators, and actually cultivate aphids on choice plants because they like to eat the ‘honeydew’ excreted by the aphids. (ICK!) That is why lemon trees that are infested with aphids also have an abundance of busy ants commuting up and down the trunks.

Trimming an aphid infested lemon tree so that it does not touch anything else, and circling the base of the trunk with axle grease, will keep the ants out without preventing predatory wasps from flying in. Just like with roses, blasting with water dislodges many of the aphids and  stranded ants; but the wasps simply get out of the way and return when it is safe. It may all seem unfair to the aphids and the ants, but is gratifying for the predatory wasps, the lemon tree and whoever cares for the lemon tree.

Posted on by tonytomeo

Insect Pathogens Prefer Less Biodiversity

Wildflowers and even weeds promote biodiversity.

Weeds grow, bloom, disperse seed and die a natural death without much trouble. This is especially frustrating while insect pathogens destroy desirable vegetation. Weeds seem to be more resilient to insect infestation and damage. Many actually are. They use nature to their advantage. Cultivation of desirable vegetation interferes with natural biodiversity.

Those who enjoy gardening do not want to consider it to be unnatural. Nonetheless, it is. It involves many exotic species that are not natural components of regional ecosystems. Breeding to improve their performance unnaturally compromises their vigor. They rely on unnatural irrigation and perhaps fertilization. They sustain many exotic insect pathogens.

Most species within home gardens could not survive for long without cultivation. Several that can unfortunately become invasively naturalized. In the process, most that benefited from breeding revert to a feral status. Some eventually enjoy more biodiversity in the wild than in cultivation. They rely on naturally beneficial insects to mitigate insect pathogens.

Insect pathogens are quite often more problematic than weeds. However, generally, they are less problematic than they were years ago. This is partly a result of improvements of modern horticulture. Strangely though, it is also partly a result of sloppier gardening. Old fashioned monoculture for big areas is passe. Biodiversity became an incidental benefit.

More species of vegetation sustain more insect species. This might not have qualified as an advantage years ago. Now, garden enthusiasts are more aware that some insects are predatory of others. Predators may not eliminate all insect pathogens, but they often limit infestations. With adequate limitation, damage is likely to be tolerable or inconspicuous.

This is one of two primary reasons that insecticides are less common now. Besides their potentially hazardous toxicity, they are simply less necessary. When they are necessary, modern insecticides target more specific insects. They can kill pathogens without hurting beneficial insects. Vegetation that too frequently needs insecticides becomes unpopular.

Posted on by tonytomeo · 23 Comments

Wasps!

P00613K
Dead wasps are the best wasps.

Wasps, hornets and yellow jackets that get established within landscapes or buildings are a serious problem. They are not so easily avoided like those out in the wild are. They are aggressive to people and pets who get too close to their nests, and attack with painful stings. Such behavior is unacceptable within the publicly accessible landscapes at work.

There are a few species of wasp, hornet or yellow jacket here. We do not get sufficiently acquainted with any of them to actually identify them. Our priority is eliminating as many of them as possible from the landscapes. Some get trapped. Others get evicted from the few nests that we locate. It is unpleasant work, but it is better than others getting stung.

Wasps, hornets, yellow jackets, or whatever they are, become more of a problem later in summer. They are just getting started for now. We were surprised to find two subterranean nests in a landscape that is in the process of being cleared for renovation. More surprisingly, they were only eight feet apart. Whomever they were, they should have been more territorial than that.

Since they are just getting started, there were not very many to get aggressive when we got too close to them. There were scarcely enough to follow as they entered and emerged from their nests. They were surprisingly easy to kill. The first nest was quite small. The second nest was a bit more concerning. We dug both out as the last few visible insects were dying.

The picture above shows a few waffle-like layers of the larger nest. Empty cells were likely left by the adult insects that were flying about and trying to defend the nest. Other cells are full of larvae that would have matured to many more of the same!

Posted on by tonytomeo · 9 Comments

Horridculture – Pesticide

P90828Pesticides are a topic that I do not talk much about. There really is not much to say about them. Only a few are used at the farm, and only while certain destructive insects or perhaps mites are active. Even less pesticides are used in the landscape. It is not that I have serious issue with them. They are just not as useful for controlling pests as proper horticultural techniques are.

Plants that we would expect to require pesticides simply are not welcome in our landscapes. We know that snapdragons and hollyhocks are very likely to be detrimentally infested with rust. Therefore, we grow neither.

Roses live in some of the landscapes only because we do what we must to help them avoid infestation by the various pathogens that they are susceptible to. They get pruned aggressively in winter so that their new growth grows faster than aphid and mildew that try to infest them in spring. Their fallen foliar debris that fungal pathogens overwinter in gets raked away cleanly.

On rare occasion, we find weeds that we would like to kill with herbicide; but we can’t because they are too close to riparian environments. With two creeks and two streams flowing through here, many of the landscapes are too close to water. We must instead pull the weeds that we can, and hope that more aggressive cover crops overwhelm what remains before they recover.

One of the few insect problems that we sometimes notice is the thrip on the rhododendrons. They are sort of always there, but had been tolerable. Aggressive pruning to stimulate vigorous new growth, and also improve air circulation, should have inhibited the thrip. Instead, the damage has been worse than it has been in a very long time. It was necessary to spray insecticide.P90828+The pictures above and below show the worst of the damage caused by thrip. The picture below compares damaged foliage on the left to undamaged foliage on the right. Thrip rasp the foliar surfaces so that they can lap up the juices within. The process causes silvery discoloration, and ruins the foliage. Young damaged foliage is likely to get crispy around the edges, or get shed.P90828++For this sort of damage, I do not mind using insecticide. However, I have doubts about this particular insecticide, or whatever it is. It is supposed to be three in one; insecticide, fungicide and miticide. How is that even possible? Insects, mites and fungi are physiologically completely different. Anything that kills all three must be very nasty stuff! Yet, it is somehow safe for bees?!

There are several active ingredients, but I do not recognize many of them. I suppose that some could be insecticidal, some could be fungicidal, and some could be miticidal. The label does not explain the functions of the various components. None are hazardous enough to warrant a use permit like we need for agricultural pesticides. This product is available at the hardware store.

I do not doubt that this nonselective ‘pesticide’ is safe for bees, even though it is supposedly formulated to kill just about anything that might bother the rhododendrons. However, since it will not kill bees, and bees are insects, I do sort of doubt that this product will kill many other insects, including thrip.

 

Incidentally, I am sorry for the delay of posting my weekly ‘Horridculture’ rant, which should have posted yesterday. It normally posts on Wednesdays. The article that posted yesterday really should have posted today instead.

Posted on by tonytomeo · 15 Comments

Horridculture – Pesticides

P90612‘Cide’ as a suffix that designates something to be killed. ‘Insecticide’ kills insects. ‘Miticide’ kills mites. ‘Molluscicide’ kills molluscs such as snails and slugs. ‘Herbicide’ kills herbaceous plants, which are presumably weeds. These examples and other chemicals that kill things that are considered to be pests are collectively known as ‘pesticides’. Many are potentially useful in the garden, since that is where so many familiar pests are problematic.
Most modern pesticides are designed for physiological characteristics that are unique to the targeted pest. They therefore kill only very specific pests, but are generally harmless to other organisms. For example, horticultural oil, which is one of the simplest of all insecticides and miticides, kills insects and mites by obstructing the exoskeletal pores through which they respire. It is harmless to those of us who conduct respiration by means of lungs.
In fact, most (although not all) commonly available pesticides, if used properly, are relatively safe for those who are not the targeted pests. (Rodenticides that remain toxic to predators who eat afflicted rodents are some of the exceptions, but that is a topic for later.) That is why I have no compunction about using such pesticides. When necessary, I would use them on the farm, in the landscapes that I so often work in, or in the home garden.
However, such pesticides are almost never necessary. Seriously. I would not refrain from using them, but the need for such use almost never presents itself. Insecticides and, to a much lesser extent, miticides are sometimes applied on the farm (although I have not been there to apply any in a few years). I applied a minor fungicide for rust on English daisies in a landscape more than a year ago. Otherwise, pesticides are almost never necessary.
It is not that there are no pests. There most certainly are. Roses get aphid. Rhododendrons get thrip. Snapdragons get rust. We just deal with such pests without much pesticides.
There are so many alternative horticultural techniques to use instead. We prune roses so aggressively in winter that they regenerate faster in spring than the aphid can keep up with. We prune rhododendrons to eliminate much of the congested and sheltered inner growth where thrip tend to proliferate. Snapdragons are so susceptible to rust that we probably will not grow them again. Pests are not eradicated, but are reasonably controlled.
All too often, the problem with pests is not the pests at all, but improper horticulture.

Posted on by tonytomeo · 25 Comments

Just When You Thought It Was Safe To Go Back To The Park –

P80722You would think that those who maintain the County Parks would be prepared for anything. They nearly are. They know how to deal with gophers, moles, voles, weeds, flooding, all sorts of unpleasant weather, and of course, spontaneous limb failure of massive trees. They apparently did not plan for this one.
This improvisation with a bit of dirty old plywood and a felt marker certainly does not imply that they could not handle the situation. They merely lacked a sign to warn those in the Park to avoid the area where the now exterminated yellow jackets had started to build their subterranean hive. Some brave person already attacked the hive with a can of insecticide that can be sprayed from a distance, waited for returning yellow jackets to die, and finally dug the hive up. The sign is only there because of the possibility that some yellow jackets might return much later, and that those who could return may not die now that the excavation of the hive mixed soil with the insecticide.
This was NO simple task. Yellow jackets and wasps are NASTY! I found it necessary to exterminate a hive of wasps just last summer. Wasps do not pursue their assailants so aggressively, and the particular wasps that I exterminated were not so numerous. I am certain that it was considerably more risky for whomever sprayed and dug the hive that was below where this warning sign is now.
When yellow jackets and wasps are flying about and annoying people, but their hive can not be located, it is sometimes necessary to put out traps. These traps are particularly useful in trees that are infested with scale or aphid that excrete honeydew that attracts wasps and such. The instructions that come with the traps are rather amusing. They include a rather extensive list of the various species and varieties of wasps and yellow jackets, with pictures of their distinctive coloration and patterns, so that they can be identified. I do not want to get acquainted with them. I just want them DEAD!P80722+

Posted on by tonytomeo · 16 Comments

My Philosophy On Garden Chemicals

70927lthumbspareI have very few reservations about using chemicals in my garden. I bet you did not expect to read that. It is the quick and easy explanation about my philosophy on garden chemicals. Almost all chemicals that are available to the general public are reasonably safe if handled and applied properly. I am actually more concerned about the larger volumes of chemicals used in the landscape industry, and applied by technicians who can not read the labels or write their use reports. Yes, it happens. Anyway, some of the sugars, salts, preservative and other components of some of the food I eat is more dangerous than chemicals I use in the garden.

That is because I use almost no synthetic chemicals. I have almost no use for them. I only occasionally use semi-synthetic fertilizers like fish emulsion. Just about every disease or insect problem I have encountered in my own garden was most efficiently controlled by cultural methods or simple home remedies that have been effective for centuries, or even thousands of years, long before the first and worst of the really nasty garden chemicals were invented less than two centuries ago.

That certainly does not mean that all home remedies are completely safe, or even any safer that some of what are considered to be ‘chemicals’. I mean, they are supposed to ‘kill’ things. Tobacco is unfortunately toxic, and kills many people quite regularly. That is precisely why a cigar butt or a few cigarette filters can be simmered into a tea to spray onto small potted plants, like fuchsias, to kill aphid. Adding a few drops of dish soap makes it even more effective (although in a different way). Is it toxic? Yes. Am I concerned about it? Not really. Although, it would be nice if no one used tobacco anymore.

Dish soap that so many of us use as a ‘natural’ remedy for aphid is almost as effective for immediate kill even without tobacco tea, but lacks residual toxicity. Because it is necessary to use a slight bit more soap if it is used alone, it is more likely to damage tender foliage. Also, most dish soap is actually less ‘natural’ than tobacco is! Homemade soap made from bacon fat may seem to be more natural, but the fat contains of all sorts of unnatural nitrates. It certainly does not bother me any; but those seeking totally natural remedies should know. (They probably should not eat bacon anyway.)

What do I do for peach leaf curl? Nothing. Well, nearly nothing while the disease is actively ruining foliage. However, while the trees are bare through winter, I prune them very aggressively. Pruning is done so that the trees do not overburden themselves with fruit, but it also stimulates vigorous vegetative growth the following spring and summer. After bloom, while peach leaf curl is busy ruining the first phase of foliage, vigorous vegetative (non-fruiting) stems are busy speeding beyond infection with reasonably healthy foliage. Inadequately pruned trees lack vigor, and are therefore more susceptible to the disease.

The worst of the damaged foliage lower in the canopy falls away as it gets replaced by healthier foliage. It should be raked and disposed of (not composted) because spores of the disease overwinter in the fallen foliage. I actually prefer to pluck much of the damaged foliage from the trees because, technically, it dispersed spores more efficiently while still viable and actively infected. Does this eliminate the disease? No; but neither does spraying chemicals.

Does putting ‘Tanglefoot’ or axle grease around the trunk of a lemon tree infested with scale eliminate the scale? Of course not. It merely keeps out the ants that cultivated the scale. (Ants have a symbiotic relationship with the scale because the ants consume the honeydew excreted by the aphid. Ick!) Without the ants to herd them around and protect them from natural predators, the scale are not so prolific. You might not even know they are there. ‘Controlling’ them just might be better than ‘eliminating’ them with a chemical insecticide. Besides, it leaves something for their natural predators to consume so that they are there when we need them.

After centuries of breeding plants to do what we want them to do and behave very unnaturally, we really should consider how to get nature to do some of the work it really wants to do ‘naturally’.