Attack of the spider mites

I bought a pot plant from Bunnings a couple of years ago.  The tag says it’s a Codiaeum Croton. It doesn’t flower, but has nice leaves with red and yellow patches.  It doesn’t seem to like too much water, so I soak it once a week, then let it dry out before watering again. I fertilise it a few times a year with a general purpose fertiliser. It’s sitting on a bookshelf just inside a window, and gets direct sunlight in the mornings, and indirect sunlight for the rest of the day.

It’s been really healthy, except that earlier this year it started losing new leaves as quickly as they were growing.  I couldn’t work out what was going on, because I hadn’t changed the way I cared for the plant.  Then two months ago I noticed a fine cobweb forming on the branches where the leaves were sprouting.  I had a pest!

Although I could see the cobwebs, I wasn’t able to see any little critters crawling on the plant. I did some Googling but didn’t have much luck identifying what was building the cobwebs, so I turned to Google+ and searched the Communities there for someone who could help.  I came across the Urban Gardening Community where I posted my question.  Within a few hours, a friendly group of people shared their experiences with me.  It seemed my plant was infested with spider mites.

Some of the suggested treatments were to provide more sunlight; improve the plants soil by using gritty mix; applying a pesticide to kill the mites; regularly spraying the plant with water to dislodge the mites.

Since my plant had been happily living in the same location for so long, I didn’t think the level of sunlight was too much of a problem so I decided to leave it where it was. The soil could definitely do with some work because I haven’t repotted the plant since I bought it. I still haven’t done this, but having read about gritty mix I think it would be good for the plant’s general health to repot it in better soil. I’m not really opposed to using pesticides, but figured I’d give the water method a try first since pesticides can be pricey and water is freely available.

If you check out the page on Wikipedia, spider mites can develop from newly laid eggs to sexually mature within 8 days, then lay 20 eggs per day for up to 4 weeks – that’s up to a total of 560 eggs per female! The purpose of spraying the plant with water is to dislodge the eggs and break the reproductive cycle until the mites die off.

Once a week I took the plant outside on the concrete driveway (I didn’t want to spray the mites onto any other plants) and using a spray bottle with the nozzle adjusted to “jet” I squirted each leaf from above and below including around the stalk where the leaves were growing. While spraying with one hand, I supported the leaf using my other hand because I was concerned they would fall off with the force of the water – something I was keen to avoid since the plant was already losing leaves without any assistance from me.

I’m pleased to say that after 6 weeks of treatment the plant is now healthy, cobweb free and growing some strong new leaves which you can see in the photo below. You’ll also notice all the marks on the stalk where the leaves had previously been chopped off by the mites.  I haven’t sprayed it for two weeks, and there doesn’t seem to be any sign of the spider mites returning, although I’ll be monitoring it closely to make sure they don’t come back. Next steps will be to head to a nursery and repot the plant with better soil so it’s generally healthier.

A huge thank you to everyone from the Urban Gardening Community for their help!

My healthy Codiaeum Croton after the water spray treatment
My healthy Codiaeum Croton after the water spray treatment
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