Aphids are a normal part of life and are not immediately a problem.
At this time of year, combined with the dry spell we have had outside, it is peak season for aphids. Fortunately, having aphids on your plants is not an immediate problem, although we notice that many of our growers perceive it that way because they worry about the impact on their crops. You might feel the same way, and we understand that.
Strategy against aphids
With a few exceptions, fortunately, the extent and impact of aphids are limited (it might not feel that way, but believe us, it can be much worse). Ideally, we want no aphids at all, but if conditions are favorable for them, their presence is inevitable. An effective strategy against aphids is therefore to ensure an optimal army of natural enemies that inhibits and reduces the aphid population throughout the season, so that our plants experience a minimal impact. Consider:
- ladybugs of various types
- parasitic wasps of various species
- hoverfly larvae
- lacewing larvae
- gall midge larvae
Most of them, incidentally, are not visible to the naked eye or are difficult to recognize!
Advantage of the greenhouse compared to an outdoor vegetable garden
An important difference compared to an outdoor vegetable garden is that this strategy is much less effective, because you cannot keep natural enemies in your garden. In a greenhouse, that is different; on that point, we have a significant advantage.
Spraying with household and other organic remedies?
Lately, however, we have been hearing that some people are combatting their aphids with mixtures of water, green soap and/or vinegar, rubbing alcohol, and neem oil. This seems effective in the short term, as the aphids decrease after spraying with this, but you will undoubtedly notice that the aphids return very quickly. This is because the conditions are still present, and the natural enemies are also killed by these remedies. The brakes that were in place in your garden have therefore been removed. If we all do this, we unintentionally give the aphids free rein. In the short term, after spraying, you see results and think you are doing a good job, but in the long term, we are actually making our plants vulnerable. Incidentally, this also applies to other pests, as you might also be killing the predatory bugs that fight whiteflies.
Conclusion
So do not use remedies such as green soap, vinegar, methylated spirits, and/or neem oil! These agents are not selective. In other words: if it kills the aphids, it also kills the natural insects. Let nature do its work, because they are present in the greenhouse 24/7 looking for aphids :-) Finally, the mechanisms by which our natural enemies work are different, complex, and not always a matter of 'insect eats aphid'. We are looking into how we can explain this better.💚
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