Xtremehorticulture

Look for Plants Dying Because of Grubs

This is the time of year when grubs are feeding on the roots of plants. Many of these types of grubs are the same types that feed in compost piles. Some people refer to them as “compost worms”. Grubs feeding on the roots of Lantana The adults of these compost worms are frequently large beetles that we see flying in June and July. Grub Guard is one of the products containing beneficial nematodes The eggs of these larvae or worms were laid in March. If there are lots of them, their feeding in the months of March, April and May can cause plants like Lantana and agave to decline and even die. There are organic options. I personally have not used them but I have received good reports on the use of both beneficial nematodes and bacteria specifically designed for grubs.The bacterium is usually referred to as “milky spore”.The nematodes are usually referred to as “beneficial nematodes”.These do not kill grubs immediately but do have a long-term effect in keeping the populations low over a long period of time. Look for the words Steinernema carpocapsae in the ingredients. Control of these immature insects is usually accomplished with applications of chemicals as granules or a liquid diluted in water and poured around the roots of the plants. Sprays or dusts applied to the leaves or foliage will not control these types of pests. This is the insecticide that contains imidacloprid. One of the most effective chemicals has imidacloprid, as an active ingredient listed in its label and sold by any nursery, garden or box store. But any chemical listed for controlling “grubs” should work and is permitted as long as it includes the plant that your treating on its label. One word of precautionon the use of imidacloprid; It has been implicated (but not proven) to possibly contribute to some environmental problems including colony collapse disorder of honey bees (CCD). Research implicating imidacloprid in CCD If you do use this product, I would not apply it to flowering plants and only apply it as a liquid, soil drench and not as a foliar spray. If you have any further questions contact me through my email, [email protected], or on my blog Xtremehorticulture of the Desert.

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Grubs Feeding on Lantana

Q. This season our Lantana has done poorly. For each plant we dig up there appears a bunch of grubs. What’s going on? A. I was alerted to this problem by a reader. The Lantanas were not doing well. That is surprising because they grow like weeds in the Mojave desert with a little bit of soil improvement, fertilizer and water.  When they dug this Lantana to replace it, they found these grubs in the hole. Grubs like to feed on soft, succulent plant roots. They are general feeders so they will munch on many different plant roots. Fortunately they are pretty easy to control with traditional pesticides as a liquid a soil drench and organic pesticides.  The organic pesticides that seem to work on a natural oil-based products such as thyme oil, Rosemary oil and others. They can also be controlled with insecticides made from bacteria or beneficial nematodes. They come in a variety of trade names but look for them in your organic section of the pesticides. Grubs that were feeding on the roots of a Lantana. Taken by the reader.

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