Have been hearing about significant Helicoverpa larvae numbers being present in our current chickpea crops throughout the state.
With temperatures starting to reach an average daily temperature of over 15 degrees, true flowers on our chickpea plants will begin to form, followed by pod set and the start of seed filling.
With these stats in mind, what are these Helicoverpa larvae eating in our chickpea crops prior to these temperature thresholds, during the sterile flowering stages?
Mostly, they are consuming leaves or foliage, not necessarily flowers, and definitely not pods at this stage.
My own experience in chickpeas at this stage suggests that quite high numbers of Helicoverpa larvae can be tolerated.
By high numbers, I am referring to up to ten larvae per square metre.
Without knowledge or experience, you could end up spraying your chickpea crop quite a few times if you simply use the basic grub or larvae threshold throughout the vegetative stages and beyond.
I proffer this advice to you all based on my years in the paddock, backed up by solid research done by DPI entomology staff some years ago.
It is also a chance to get off the bandwagon of overapplying conventional insecticides to our seasonal Helicoverpa population.
Now, I don’t mind applying some lower rates of Vivus Max, our premier biological insecticide with NPV (nucleopolyhedrovirus), during the vegetative stages and even into the early flowering stages of our favourite winter pulse crop, especially when lots of larvae are present.
There are plenty of advantages to this early NPV application practice, such as reducing the potential for insecticide resistance to develop in our top-tier insecticides like Chlorantraniliprole, Emamectin, Methoxyfenozide (Jemvelva), and even the slightly older product, Indoxacarb.
By using this biological product, Vivus Max, in our vegetative or early flowering stages, when larvae are actively foraging, there is a good chance this particular crop will only require a single insecticide application.
That’s a good result all round, and it certainly eases the pressure on rising insecticide resistance levels and the risk of breaching any insecticide withholding periods.
Plus, it helps avoid the need for late ground rig applications, which can knock off pods and squash important yield-bearing branches.
