I often explain why making multiple releases of biocontrols makes sense in human terms. I typically do this over the phone, but I don’t think I’ve ever written about my oft-used analogy. The one I resort to most often is to compare releasing of biocontrols to the US Civil War tactic where rows of infantry — the Line — would keep pressure on opposing forces by creating an unceasing barrage of fire.
They did this by forming rows or lines of infantrymen at least two rows deep. The thinking was that while one row was firing their weapons, the other row could load and ready theirs. Weapons technology of the time required a considerable period to prepare a weapon for another shot so this tactic allowed for a nearly unbroken wave of deadly salvos.
The whole “considerable period to prepare the weapon” aspect may ring familiar to biocontrol practitioners. The weapon preparation phase, as it pertains to biocontrol, would be when we’re waiting for emergence, hatch-out, or second generation presence (or perhaps even for your next order to arrive).
During these times, when we’re waiting for, say, a second generation presence (which, by the way, doesn’t always happen), there is a period of no pressure on pests. In the case of my Civil War analogy, this would mean that while a single row of infantry is readying for another salvo, there is no second row available to keep pressure on opposing forces. Said forces would get closer and better establish as a result. And if both sides are in this position, as may be the case as it involves biocontrols, the war wouldn’t end.
A release of biocontrols is the Line or row one. A second release of biocontrols is another Line or row two. Row two keeps the pressure on the enemy while row one readies itself (or row three prepares if the case applies, such as if row one has second generation offspring) by laying eggs, pupating, etc. — the specifics are dependent on the agent and its form. This logic keeps constant biological pressure on pests preventing them from advancing and further entrenching. And for the best results using biocontrols, we don’t want to give pests an inch.
Some might think that we can release one male and one female good bug into a garden and let nature take its course, without such aggressive tactics, but it’s just not so. To try that one doesn’t even need to release biocontrols as simply not spraying will allow mother nature to put things in order. But that takes too long — she’s too slow to react. Waiting for nature to balance the proportions of pests to good bugs in a garden can take many seasons and possibly never happen to the degree we need as growers.
Using biocontrols isn’t about helping nature restore balance — though that’d be nice. It’s an accelerated process. We’d like to balance out the pest to good bug proportions in the garden, but instead we aim to completely imbalance things for a period. We want to dominate and overthrow the growing or established pest population. It’s a coup. Balance will still occur, but after the fact. After harvest; after success. Nature can sort it all out, as long as we ensure our good bugs don’t become pests themselves, which, as programmed by nature, they cannot.
Instead of adding a couple of good bugs to a lot of pests and letting nature balance things from that weak and ill-fated starting position, the better idea is to let nature balance things from the position of having too many good bugs (who’ve wiped out the pests). As long as pest conditions are in our favor, Mother Nature can take her sweet time making our good bugs dwindle, die, or go elsewhere, as any unnatural surplus surely will.
To get there, though, this usually involves not just hitting them, but also kicking them while their down. A one-two, or more, punch. When row one is reloading, row two will keep the pressure on. And in order to overthrow a pest population, especially when using something so notoriously slow as nature, we must hit hard. This is the strategy that drives our biocontrol release tactics. Release one, just as they stop feeding or whatever they are sent to do, are relieved by release number two, and so-on and -so-forth as the case may be. The pests, instead of catching a break as nature would offer on her own, get hit again. It works.
Susan in the Pink Hat responds:
Posted: July 19th, 2010 at 10:30 am →
But don’t many biocontrols affect the good predatory bugs as well as the bad?
And what biocontrol sequences are you suggesting?
Mike Cherim responds:
Posted: July 19th, 2010 at 1:24 pm →
When you write “good predatory bugs,” do you mean naturally occurring enemies, Susan, or other introduced biocontrols? Regarding sequence, I’m not sure I understand what you’re asking. Sorry.