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I was wondering if any one has a good way of controling thrips and
fungas gnats in S/H, I have tryed neem, systems, BTH and soaking, I still have the freeking critters (the gnats I can stand, but I HATE thrips) The other is how can you prevent damping off, every time I deflask seedling they loose all their leaves. Now 2 months later the little suckers that have survied so far are putting out more leaves, but I lost about half the batch, I think that my culture is good, 70% humidy, 65-75 F, a week in a 1/2 gal bag gradually hardening them off before putting them onto my grow rack. This is killing me. BTW Ray, stanhopea seem to do well in hydocorals for deflasking. Jack |
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"Jack" wrote in message oups.com... I was wondering if any one has a good way of controling thrips and fungas gnats in S/H, I have tryed neem, systems, BTH and soaking, I still have the freeking critters (the gnats I can stand, but I HATE thrips) I have no idea whether this method will have unintended consequences, but an even layer of fine white sand about 1/4" thick will quickly smother your annoying gnats. |
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On Mon, 7 Aug 2006 19:24:26 -0400, "TQ" ToweringQs AT adelphia.net
wrote: "Jack" wrote in message roups.com... I was wondering if any one has a good way of controling thrips and fungas gnats in S/H, I have tryed neem, systems, BTH and soaking, I still have the freeking critters (the gnats I can stand, but I HATE thrips) I have no idea whether this method will have unintended consequences, but an even layer of fine white sand about 1/4" thick will quickly smother your annoying gnats. How can you put sand on top of S/H? It will work down into the PrimeAgra or expanded clay. SuE http://orchids.legolas.org/gallery/orchids |
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1) Dealing with thrips on plants growing in semi-hydro culture is no
different that dealing with them on a plant grown any other way - a good contact/systemic insecticide is needed. They live and reproduce strictly in the vegetative tissue. 2) Fungus gnats indicate the presence of decomposing organic matter, which suggests that you didn't remove the organic potting media components well enough before moving the plant into S/H. A decent contact-killer insecticidal drench should do it. -- Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies, Artwork, Books and Lots of Free Info! "Jack" wrote in message oups.com... I was wondering if any one has a good way of controling thrips and fungas gnats in S/H, I have tryed neem, systems, BTH and soaking, I still have the freeking critters (the gnats I can stand, but I HATE thrips) The other is how can you prevent damping off, every time I deflask seedling they loose all their leaves. Now 2 months later the little suckers that have survied so far are putting out more leaves, but I lost about half the batch, I think that my culture is good, 70% humidy, 65-75 F, a week in a 1/2 gal bag gradually hardening them off before putting them onto my grow rack. This is killing me. BTW Ray, stanhopea seem to do well in hydocorals for deflasking. Jack |
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Thanks, I have alot of algea growing in this pot, I removed all the old
moss before repotting, Guess that I'll have to get some phytosan and drench it in malithion, actually all my orchids because where there is one thrip in one plant you have thrips in all your plants. Wow I hate those suckers. Jack BTW I have an Onc. Pacific Skys that is in spike, I guess that I am used to phals and catts because I am getting impatient for it to bloom and all it is doing is branching out the spike. |
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The life cycle of a thrip is fast; about 2 weeks, depending on species and
temperature. Generally speaking, the warmer it is, the faster the life cycle. All but one stage has piercing/sucking mouthparts. They can esialy get through screens and come inside a greenhouse or indoor growing area from outside populations. In some species all stages have wings, from the newly hatched instars to the adult, and in other species wings are missing during some stages, leaving them a period of only a couple days where they must crawl/walk to find food. As you know they are tiny. Without a loop, it is not easy to tell a fungus gnat from a thrip. The easy difference is in where they feed. Fungus gnats larvae feed almost exclusively on decaying material near the upper surface of soil/pots/potting media/scummy ponds/refrigerator drip pans, etc..... Adults fungus gnats exist only to fly and mate and don't have mouth parts. Few if any species of fungus gnats eat live plant roots, but there are plenty of other 'decomposing' larvae that do and they all look like each other to the giant human eye observing them. Thrip Eggs are laid on plant tissue, usually leaf and more often flower tissue and newly hatched larval instars will begin to feed on any part of the plant which presents sap/fluids containing nutrition. Populations tend to rapidly take on the coloration of whatever they are feeding on and this leads to common names, like "Green" or "Yellow" Tobacco Thrip, or "Purple Dendrobium Thrip," etc... when in reality they may not be plant specific species; just rapidly adjusting generational camouflaging eveolved as a form of protection. Within about 72 hours the larva will molt through two stages all the while eating whatever tissue they are living on. Once the third stage instar begins they stop eating some may even develop wings, fly off or simply crawl down into moderately or well decayed potting media to pupate. Like fungus gnats, this instar requires potting media that is very moist and on the decomposed side in order to do well. Dry and/or new potting media will make it hard for both fungus gnats and 3rd stage thrip larvae to survive in it. The hatching pupa are responsible for biting humans and causing skin reactions: they literally will pierce and suck any tissue that is moist, including skin. The fourth stage pupa, is where they turn into fully mature adults ready to mate and reproduce. Females lay eggs which will hatch even if not fertilized. Eggs produced from fertilized females will yield offspring of either sex; those laid by unfertilized females will hatch into only males. I write all this because you must address a thrip problem on all parts of the plant and environment where any moist living or decaying tissue, (plant or animal) exists. :-) "Jack" wrote in message oups.com... Thanks, I have alot of algea growing in this pot, I removed all the old moss before repotting, Guess that I'll have to get some phytosan and drench it in malithion, actually all my orchids because where there is one thrip in one plant you have thrips in all your plants. Wow I hate those suckers. Jack BTW I have an Onc. Pacific Skys that is in spike, I guess that I am used to phals and catts because I am getting impatient for it to bloom and all it is doing is branching out the spike. |
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So, wash out the grow racks, treat heavily with systemics, flush with
contact, what the hell some throw some neem and phytosan on just for fun AKA Nuke them all. got it, no wonder they are such a freeking pain, in the past I could manage to keep them from doing serius physical damage to my plants (yeah yeah I know about virus and all that) but could not manage to elimniate them. I will have to make a dedicated effort Thanks Jack |
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"Thrips" is a plural noun, like "deer." One deer, many deer. One thrips, many thrips. J. Del Col |
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You've had lots of responses on the thrips. The only thing I would add is
that we generally find it necessary to spray more than once. My usual protocol is 3x, about 7 days apart. If you find you have to do it again after that, change chemicals. OK - 2 things. Soap is a good additive to most sprays, but test for compatibility first (mix up a couple ounces of whatever you plan to spray the night before, add a couple drops of soap, shake well, and then the next morning see if the solution is all still suspended or a bunch of gunk has settled out). If it stays mixed, the soap will provide your contact kill and also act as a sticker-spreader for the systemic. Works for potted plants in a mix of mostly lava rock; your S/H method might make a difference, so someone else who uses that and knows should pipe up here -- will the soap residue be harmful in that situation? Fungus gnats are annoying, but I haven't been able to see that they do any plant or flower damage, and here they usually die on their own (we've occasionally imported some on purchases, never seen any develop onsite). So I can't help on that. On the damping off on plants coming out of flask -- how are you taking them out? There have been a couple-three recent posts about different methods .... Kenni "Jack" wrote in message oups.com... I was wondering if any one has a good way of controling thrips and fungas gnats in S/H, I have tryed neem, systems, BTH and soaking, I still have the freeking critters (the gnats I can stand, but I HATE thrips) The other is how can you prevent damping off, every time I deflask seedling they loose all their leaves. Now 2 months later the little suckers that have survied so far are putting out more leaves, but I lost about half the batch, I think that my culture is good, 70% humidy, 65-75 F, a week in a 1/2 gal bag gradually hardening them off before putting them onto my grow rack. This is killing me. BTW Ray, stanhopea seem to do well in hydocorals for deflasking. Jack |
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Webster agrees. #@%#$&! dictionary.
wrote in message oups.com... "Thrips" is a plural noun, like "deer." One deer, many deer. One thrips, many thrips. J. Del Col |
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I will have to try adding soap.
The flasklings I take them out, they are shipped in twirl packs already taken out of the flask, but are not washed, I seperate them and place them in the compots that are already soaked with superthrive, 1/4 strength fert, and ironite transplant. I place them in 1/2 gal baggies and spray them with neem oil. I open the baggies up more each day for a week then put them in my grow rack on the next to top shelf with full shading and a grow light, 2 40w flourencents. I water them when they get dry and try to keep the medium universially moist, alittle dry between each watering, about every 2 days. temp 75F, humidity 65% - 75% with a fan running on the shelf below them which keeps the air moving. I don't think that I am over handling them. but some times I think that I am letting them get too dry, but if I let them stay wet I have problems with mold. I Know that this a subject that has been covered before, but i think that I am doing it right and still have greater than 50% fatality rate. Jack |
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Jack,
Personally, I'd skip the neem oil, and take a bit longer to harden them off. -- Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies, Artwork, Books and Lots of Free Info! "Jack" wrote in message oups.com... I will have to try adding soap. The flasklings I take them out, they are shipped in twirl packs already taken out of the flask, but are not washed, I seperate them and place them in the compots that are already soaked with superthrive, 1/4 strength fert, and ironite transplant. I place them in 1/2 gal baggies and spray them with neem oil. I open the baggies up more each day for a week then put them in my grow rack on the next to top shelf with full shading and a grow light, 2 40w flourencents. I water them when they get dry and try to keep the medium universially moist, alittle dry between each watering, about every 2 days. temp 75F, humidity 65% - 75% with a fan running on the shelf below them which keeps the air moving. I don't think that I am over handling them. but some times I think that I am letting them get too dry, but if I let them stay wet I have problems with mold. I Know that this a subject that has been covered before, but i think that I am doing it right and still have greater than 50% fatality rate. Jack |
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I got an email from someone who reads this newsgroup who I know to be very
knowledgeable but who only lurks here. He suggested I consult my pest management textbook on thrips with regard to their soil dwelling stage. The text book points out that Thrips pupating in soil are very susceptible to moisture and the associacated fungus problems. So in this respect, the natural controls on them are just the opposite of fungus gnats. Damp decomposing media posses a greater threat to their life-cycle than dry new media. They can be easily drowned in just water and or fall prey to the same decomposing fungal organisms that are breaking down the media. I suspect thrips live cycle would be easily disrupted in the semi-hydro method of potting orchids if they have no place else to pupate. "Al" wrote in message ... Once the third stage instar begins they stop eating some may even develop wings, fly off or simply crawl down into moderately or well decayed potting media to pupate. Like fungus gnats, this instar requires potting media that is very moist and on the decomposed side in order to do well. Dry and/or new potting media will make it hard for both fungus gnats and 3rd stage thrip larvae to survive in it. |
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Al wrote: As you know they are tiny. Without a loop, .... That should be a "loupe." 10X would be best. Obligatory songs: "Here We go Loop-de-Loop." "Little Latin Lupe Lu." J. Del Col |
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dam, your good. ;-) Ask me about my electric wench some time. You don't
get a.b.p.o do you? However, it's definitely a loop I was speaking of. I made it myself with some clear cellophane stretched over one end of an old bubble blowing wand left over from one of my recent childhoods. I couldn't find the loupe that I was required to buy for my pest management class so I had to improvise. This reminds me of my favorite exchange from one of Rex Stout's Nero Wolfe novels. In it Wolfe had maneuvered one of his suspects into the red chair and was making him nuts with his erudite pedantic style of interrogatory interlocution until the man simply could not take it any more. He said, "I came here to find out what you've done with my wife, not to have my grammar corrected!" To which Wolfe dryly replied, "I'm not correcting your grammar. I'm correcting your diction." .....I guess you had to be there. Anyway, you may correct either of mine any time you like and I'll try to be more careful. It's just reassuring to know somebody actually reads this cwap 'o mine that closely, sense most of it is so obliviously devoid of common cents. Al Most probably lost in one of his many childhoods ...or is he trying to avoid a mountain of repotting chores? wrote in message oups.com... Al wrote: As you know they are tiny. Without a loop, .... That should be a "loupe." 10X would be best. Obligatory songs: "Here We go Loop-de-Loop." "Little Latin Lupe Lu." J. Del Col |
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