Apparently, the summer weather will be characterised by the La Niña weather pattern. For our region, this will mean more north-easterly wind flows with warmer, more humid conditions and more frequent rainfall. This is excellent news for gardeners that get tired of continually watering the garden, and plants in general will relish the more tropical growing conditions.
As always, there will be a fly in the ointment, or in this case a plague of pests in the garden. Warm humid weather will inevitably lead to an explosion of various insects and diseases. It’s already started in our garden, with an onslaught of bronze beetle on the boysenberry and raspberry plants, which are their preferred food source. The feijoa shrubs and gardenia are also looking very tatty around the edges as these are also high on the bronze beetle menu. In addition, each time I happen to brush past the grapefruit tree I’m greeted with a puff of citrus whitefly.
And this will just be the start!
My go-to solution for most pest problems these days is a mix of liquid seaweed and neem oil, for a general plant tonic spray and pest control, or a more grunty mix of neem oil and insecticidal soap for problematic pest outbreaks.
The first combination is relatively soft on the plants and beneficial insects. The seaweed helps to feed the plants, reduce disease and act as a deterrent to some insects, while the neem does general pest control. An overall garden spray every two to three weeks or so with this combo is quite effective.
The second combination is tougher on plants. For some sensitive leaved plants, such as tomatoes and beans, I wait until the rest of the garden is sprayed, then dilute the remaining spray by half before spraying these plants to avoid the worst leaf damage. The soap plus neem combo is good at controlling most insects, even the hard to kill ones like bronze beetle and green shield beetle. I use this combo as a more targeted spray. For example, right now I’m using it on the berry fruit for bronze beetle and on the citrus for whitefly. Later, I’ll use it on cannas and other soft-tipped plants when the passionvine hoppers emerge, then on the tomato family when the tomato-potato psyllid emerges in late November, and so on through the rest of summer and autumn.
Leaf burning is more likely during hot, humid conditions. If you can, wait for a cooler day and spray in the evening.
Spraying in the evening is also less likely to affect beneficial insects, particularly honeybees, as even though these sprays are relatively non-toxic, a blast of this while the bees are foraging is not going to go down well. An evening spray will also mean the liquid stays on the plants and the insects for longer before drying, giving extra time for the active ingredients to do their job.
Good coverage is important for relatively low toxicity sprays such as these. If I’m doing a full garden spray I use a backpack sprayer to get more pressure to penetrate into the shrubbery. I have the nozzle turned upside down so the spray is going mostly on to the underside of the leaves, with the overspray then settling on the upper surfaces.
Once the plant is literally dripping, a quick spray over the top will get any missed upper surfaces. This finishes the job, and I can go back to enjoying a tropical summer.