How To Stop These Two Pests From Destroying Your Plants

When nature and so many other variables beyond our control determine, at least to some extent, what the fruit of our gardening efforts will be, it’s easy to lose hope in the garden or the landscape we’d been dreaming of. Frosts may come late and freeze our tender seedlings. A gaggle of squirrels may dig all of our bulbs. The rains may disappear from April to October. The dogs, the bugs, the heat. The struggle is real. But what’s interesting to notice about plant people is that their practice – their gardening, their landscaping, their hanging basket making – is an exercise in hope. We hope that this year will be better. We hope that this new variety of begonia will bloom better. We hope that our new fertilization practices will pay off. We hope.

Though it can certainly be discouraging at times, gardening of any sort is, at its core, an exercise in hope. For all but those who dismiss plants altogether after their first hanging basket dries and withers, hope is inseparable from their practice. And what a life-affirming practice gardening, then, is!

So, in that spirit, we want to raise a flag of warning followed by an assurance of hope.

Over the next few weeks, all of our spring bulbs are going to be popping up. Shortly thereafter, our perennials and shrubs will start reaching for the sun, as well. It’s a very exciting time for any and all who enjoy the outdoors, but the exuberance can quickly turn to strife if we’re not looking through the landscape and garden with eyes wide open.

Here’s the flag of warning: as much as you and I enjoy the new colors and the new life that our gardens produce in the springtime, there are a few pests that also enjoy that new growth. These are aphids and spider mites. Both of these, if left unchecked, can and will multiply in number very rapidly. If left unchecked, then, they can inflict some serious damage on your landscape plants.

Aphids are a pest to look out for in early spring.
Aphids are a pest to look out for in early spring.

Aphids are an insect that, as eggs, usually over-winter in the bark and in any crevasses that they can find on a plant. In the spring, then, not long after the tender new shoots of plants such as spirea begin growing, the eggs hatch and the carnage begins. As seen in the picture, aphids don’t travel alone. When they show up, they show up in herds. Aphids are piercing-sucking insects which live only by sucking the sap (life) out of their host plant. They will be found almost exclusively on the new growth of plants since this is the easiest for them to penetrate. Though aphids won’t usually kill the plant they’re eating, they will usually prevent it from blooming (since most flower buds appear on the new growth that they’re eating) and can make the overall appearance of any plant they inhabit less than desirable.

The good news about aphids is that if they are noticed early on, they are simple to control and no permanent harm will have been done to your plants. If the numbers are few, it may be simplest to just wash them off with the garden hose. Using a spray nozzle will help with this. Or, if there are only a few small and insignificant branches that are infested, you may do just as well trimming them off and disposing of them in the nearest blazing inferno. If there are too many or if they just won’t disappear, it may be necessary to use a spray to kill them. Most garden centers and box stores have controls that are safe both for you and the environment, but not for the aphid. As with any chemical, always read the label to make sure that it will treat the pest that you want gone, and to understand the chemical’s application instructions.

Spider Mites can't bee seen with the naked eye, but you can see the damage they inflict.
Spider Mites can't be seen with the naked eye, but you can see the damage they inflict.

Another pest that we see all-too-often is the spider mite. Actually, however, we are far more likely to see that damage that they inflict than we are to see the mite, itself. Spider mites are too small to see with the naked eye, but their presence is not. Like aphids, spider mites will usually over-winter on the plant, wake up in the spring with a voracious appetite, and get busy wrecking plants. Also like aphids, they pierce the host plant and suck the life right out of them.

Unlike aphids, however, spider mites will often do enough damage to a plant to kill it altogether. And as they are too small to see, by the time they are noticed, damage has already begun. So, what will I see? As you can see in the picture above, spider mites give the leaves they’re chewing on a mottled and lighter green appearance. On closer inspection, you can see that the mottling is a result of the hundreds of needle-point sized bite marks on the leaves. The pale green of the infected leaves is a result of the mites sickening the plant by removing water and nutrients from it. Boxwood, azaleas, and Alberta spruce are some of their favorites. The picture above shows them on burning bushes.

The good news is that spider mites can also be kept from doing much damage if you’re willing to keep an eye on your plants, especially the three mentioned above. If you do notice their trademark dappling or the pale green leaves that they leave, though, a spritz of water is not going to do anything to them. In fact, they’ll enjoy it. They are most often found on plants that are hit with lawn irrigation or in landscapes that are over-watered. Again, the local garden center will have a treatment for the mites. One word of caution, though: when spider mites are the pest, multiple applications (following the labels directions) are required. It’s not a big deal, but you may need to treat them 3-4 times through the season.

Since both of these pests will either be noticeable, or will leave signs for the probing eye, and since neither of them will kill your plants overnight, their presence and treatment isn’t anything to be discouraged about. Nature is going to throw you a curve-ball this year – you already know this. It’s some of what gardening and landscaping are about – straightening nature’s curves. And really… what would you be doing this year if you didn’t have any problems to solve?

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