Phytoseiulus persimilis and Beauveria Bassiana against Spidermites!

  • Thread starter Grapefruitroop
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Grapefruitroop

Grapefruitroop

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Hi y all!
So yesterday, i spotted a beginning of a Spider mite infestation...😲
Made some researches and gladly i found that nowadays we have many alternatives to eradicate em without using poisons, and im not talking about weird homemade cococtions that will burn or trash your plants but the use of predatory mites togheter with the beneficial fungus called beauveria bassiana...

The key part of this strategy is to have a pretty high relative humidity, 70s to 80s to make sure that the lyfecycle of the spidermite is greatly slowed down while the lyfe cycle of the Phytoseiulus Persimilis is very much speed up...Those predators are fast and voracious and will hunt and kill adults ,larvae and eggs.
I also found a university article that proves that the use of the virulent fungus B.Bassiana is very effective against tthe spidermites but not affecting the predators!! wooo ho!
Also in this case the Bassiana needs pretty high relative humidity over 70s to germinate and infect the parasites....

I run a sealed room with high humidity all the time but i realize that majority of growers in vented system keep their RH pretty low to avoid mold...and thats why many times i heard complains about the effectiveness of this two potent allies in the spider mite eradication...forcing the use of poisons...

Here is some cool info i found on Phytoseiulus habits

https://biocontrol.entomology.cornell.edu/predators/Phytoseiulus.php

Humidity strongly impacts P. persimilis' efficacy. Development was observed to almost stop at humidities of 25-30%, and relative humidities below 70% resulted in a reduction in the ability of immatures to molt from one stage to another. In one study, at a relative humidity of 40% (temperature 27°C), only 7.5% of eggs hatched compared to 99.7% at 80% relative humidity (same temperature). Eggs held at a relative humidity of 50% appeared to shrivel at all temperatures from 13-37°C.

Phytoseiid mites use odors (kairomones) associated with mite-infested plants to locate their prey. When P. persimilis contacts spider mite webbing, it intensifies its search for prey.

P. persimilis has high dispersal ability and its distribution is highly correlated to that of its prey. However, its ability to disperse is dependent on the environment. If infested plants' leaves touch, dispersal is possible. When the plants have little contact with each other, dispersal is reduced by about 70%. P. persimilis moves upward on the plant in search of prey and disperses when prey is scarce. Nymphs do not disperse easily, and are left behind when prey becomes scarce.


And another on Beauveria bassiana
https://pubmed.ncbi.nlm.nih.gov/27783179/

No viable fungal hyphae were found on predator cadavers. Observations with scanning electron microscopy revealed that conidia were attached to the cuticle of predatory mites within 2-12 h after spraying with strain LNSZ-26, and had germinated within 24-36 h. After 48 h, conidia had gradually been shed from the mites, after none of the conidia had penetrated the cuticular surfaces. In contrast, the germinated conidia successfully penetrated the cuticle of T. urticae, and within 60 h the fungus colonized the mite's body.


Well....i think i found a good game plan...ill let you guys knows how things will evolve! Im so glad i dont have to get any toxic stuff !!!
☮️☮️☮️
 
Moe.Red

Moe.Red

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Interesting. I've never had spider mites but if I do I'll be looking back at your results. Good luck!
 

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