Plant pest and disease identification and solutions

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Zasso Nouka
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Plant pest and disease identification and solutions

Post by Zasso Nouka »

As it's getting much hotter now we are seeing more and more pests appearing amongst our vegetables so as I come across them I thought I might post pictures and offer some solutions that we've found to be effective.

Today we have salad that mysteriously dies

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Re: Plant pest and disease identification and solutions

Post by Funasshi »

Good stuff, ZN

Do you know from experience if using bio-pesticides does any unintentional harm to the beneficial insects who also dwell in the same area? Or are the pesticides very specific in their target range?

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Re: Plant pest and disease identification and solutions

Post by Zasso Nouka »

Thanks Funasshi,

Bacillus Thuringiensis is totally specific to caterpillars, steinernema kraussei will kill the soil living larvae of many beetle pests but has variable effects on adults, potentially it can affect kabutomushi which you may or may not consider a pest, I do when they are eating the roots of my vegetables.

As for other bio pesticides their effects can be variable, did you have anything specific in mind ?

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Re: Plant pest and disease identification and solutions

Post by Funasshi »

Ah, that's good to know. So there is some focus on what insects are targeted.
I am ashamed to admit that I have next to no knowledge about the mysterious and wonderful world of insects. So my automatic reaction when reading about bio-pesticides is to wonder about its side effects on other, good bugs. I was mostly thinking about mantis, ladybug and alike.
As reference, just googled this cute list of the nice bugs. Many of them are pest predators.
Top 10 good insects
Again, I often think about if promoting insects of this sort in one's farm will naturally eliminate the need of pesticide, or if still some additional bio-pesticide is needed on top of that. I have almost no hands-on experience yet, so I was wondering how well the friendly insects work in reality. :think:
I guess these is the question of balance, and not overdoing it. Just like a few birds can be good for your fields but not too many... ;)

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Re: Plant pest and disease identification and solutions

Post by Zasso Nouka »

Funasshi wrote:I am ashamed to admit that I have next to no knowledge about the mysterious and wonderful world of insects.
Well with summer just around the corner you are soon going to have plenty of opportunities to become accustomed to those insects in all their wonder and glory :D, although it might not seem like that when they are busy munching your prized veggies. Just think of it all as a valuable learning experience :D
Funasshi wrote:Again, I often think about if promoting insects of this sort in one's farm will naturally eliminate the need of pesticide, or if still some additional bio-pesticide is needed on top of that. I have almost no hands-on experience yet, so I was wondering how well the friendly insects work in reality.
I'm not sure if there is any gentle way to put this but predators will generally be vastly outnumbered by pests/prey, think lions to wilderbeast or some other predator/prey ratio. We've rarely found on our land that natural predators keep pests under control naturally, they do have an effect but quantifying that is not easy and some crops can be devastated. Take the humble Nekirimushi mentioned above as an example, we plant 30 - 40 thousand carrots twice a year and several times that amount of baby leaf salad. Patrolling that every day scouting for Nekirimushi would take a sizeable chunk out of your morning during which time other jobs wouldn't get done. So introducing predator nematodes in very large numbers becomes economically viable and a real time saver. The same would be true for other predatory insects, by flooding the environment with very large numbers of predators, over and above what would naturally be found completely upsets the natural balance between predator and prey and gives you the opportunity to eradicate a pest species for a short while.

Or you could use a biopesticide to reduce the pest numbers down to a level where the natural predators can then keep it under control.
Funasshi wrote:Ah, that's good to know. So there is some focus on what insects are targeted.
Yes and no, whilst something like bacillus thuringiensis is fairly specific in what it affects beauveria bassiana (Botanigard) on the other hand is fairly unspecific and will infect any insect that spray droplets land on. When using beauveria bassiana you have to be really careful not to spray beneficial insects and bees as they will get infected, so spray only in the early evening when bees are not active and always keep an eye out for praying mantis, ladybirds or other beneficials. To give you an example, right now we generally spray beauveria bassiana between rows of crops to try an kill as many young grasshoppers as we can but don't spray the crops themselves with Botanigard, that way we get many grasshoppers but don't risk hitting the praying mantis lurking amongst the crops. By reducing the numbers of young grasshoppers now we let the resident mantises control their numbers later on in the year.

When using biopesticides you have to understand how they work and their mode of action so that you can limit collateral damage to insects you want to preserve whilst at the same time getting the best results from your efforts. If one were to spray willy nilly you could cause just as much damage as using conventional pesticides. Even something as benign as neem oil can still smother very small ladybird larvae or other small beneficial insects so a thorough understanding is essential IMHO.

This is a sweeping genralisation here but flooding the environment with vast numbers of predator species is possibly more specific than using a biopesticide and apart from nematodes generally works best in a closed environment like a vinyl house.

That really is only just touching on the topic in a very brief way but nevertheless I hope it helps. Perhaps you can drop by again sometime and I can show you some of our practices.

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Re: Plant pest and disease identification and solutions

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Re: Plant pest and disease identification and solutions

Post by gonbechan »

Dear Aunty Pest Control

WTF is this walking raspberry that I see in my garden?
Is it a good walking raspberry or a naughty one?

Best wishes
Gonbechan

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Re: Plant pest and disease identification and solutions

Post by Zasso Nouka »

Some sort of caterpillar but not one I've seen before, if it's not eating vast swathes of your garden I'd be inclined to leave it but then don't blame me if next year you get invaded by hordes of it's offspring and all your plants get eaten. So maybe safety is the better course of action :think:

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Re: Plant pest and disease identification and solutions

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Re: Plant pest and disease identification and solutions

Post by Eric in Japan »

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Kids found this ball of OMGWTF on the sidewalk this morning.



They are tiny. Immature gejigeji or mukade? The whole ball of them was the worst part.
"... so, the cucumbers said to the cabbage, `Lettuce Go.`"

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