It looks like our summer is going to be characterised by warm and humid conditions interspersed with intense rainfall and periods of glorious sunny days. Fantastic conditions for plant growth also, with lush tropical looking foliage bursting out in abundance. The bugs are also having their salad days, exploding in youthful exuberance and colonising those fat and juicy stems. It’s going to be a big year for bugs, following a very mild winter.
I’ve already had to battle an infestation of tropical army worm on the brassicas using a combination of neem at 7ml/L and Success at 10ml/L, plus insecticidal soap at 10ml/L (this rate depends on the brand of soap used). This is a very effective insecticide mix to use in the home garden, as each product has a different mode of action and, therefore, insect resistance is less likely to build up.
Angela took the more hands-on approach with a gang of green vegetable bugs that had infested our winter potato crop. The old thumb and forefinger squeeze is still the most effective way of dealing with that critter, although after more than 100 squashed bugs, she was a bit over it!
An overwintering population of greenhouse whitefly in my greenhouse tamarillo, chilli and tomato crops needed three sprays of the aforementioned spray mix at fortnightly intervals to regain control. I drop the neem concentration to 5ml/L for the tomato family of plants, as they are sensitive to burning from this oil product. Now is a good time to spray the underside of the citrus leaves with this same formula to knock out citrus whitefly, which is a species that only affects citrus and results in sooty mould forming on the leaves.
It’s very important with both neem and insecticidal soap to spray either very early in the morning or in the evening, my preference as I’m not known to be an early riser. Waiting till the bees and other beneficial insects have stopped working reduces the amount of by-kill, as even though the sprays I use are considered organic and safe to use around beneficial insects, they will still be affected if directly sprayed. The other reason is that the cooler evening temperatures reduce the risk of leaf damage from burning and give the spray more time to take effect before drying.
The next pest on my list is the passion vine hopper. I’ve just started to notice the first stage nymphs (often called fluffy bums) on the new succulent growth of various plants such as cannas, hydrangeas (also sensitive to neem), heliconia, coffee, berry fruit and some vegetables. If I can knock out most of this first stage, the population will be greatly reduced later in the season.
And then it will be the turn of the tomato potato psyllid (TPP). Last year wasn’t too bad for this pest, but after a mild winter and tropical summer conditions I’m expecting an invasion. I’m keeping an ear out for the first cicadas, which I use as my guide for when the first of the TPP can be expected, a couple of weeks later. This pest severely weakens tomatoes, capsicums, chillies and tamarillos, making them more susceptible to other pests and diseases. It also carries a pathogen that causes a symptom called “yellows” which, as the name suggests, is pretty debilitating for what should be green plants.
Like the saying goes, a stitch in time saves nine. In this case, one dead bug means a lot less bugs later.
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