For anyone that grows plant commercially , you ’re well cognizant that pesticides , plant growing regulators , and plant food can all sometimes induce unwanted effect or damage to crops ( phytotoxicity ) . product used for greenhouse sanitation , such as those used to strip biofilm from piss line , can also be a germ of unexpected phytotoxicity ( or " phyto " ) , if used incorrectly .
Typically , symptoms of phytotoxicity can let in leaf equipment casualty , flower damage , plant stunting and etymon scathe . Phyto usually occurs fairly quick on ornamentals ( 2 - 4 days ) , but can take up to 7 - 10 day , reckon on the plant , the chemical agent ask , its program ( spray vs. drench ) and the environmental conditions ( with heat / sun often exacerbating symptom ) .
Classic leaf margin burn on Cyclamen from phytotoxicity after spray Pylon . picture by OMAFA .
Aphicides and Phyto : what we ’re seeingKontos : Alternate aphicides to Beleaf ( flonicamid ; Aria in the U.S. ) were cover in a recent Wiley Post . Kontos ( spirotetramat ) , one of the most effective intersection against aphids , is also a Cartesian product that growers are familiar with when it comes to potential phyto . as luck would have it , the manufacturers are mindful of this , and the phytotoxicity admonition on the Kontos label is quite comprehensive . However , newer chemistries , or those which have not been in big rotation until recently , may catch cultivator by surprise .
This was the case in the last calendar month or so with two product that are being used more frequently now that Beleaf appear to have less efficaciousness on sure farm .
Altus : Both Altus ( flupyradifurone ) and Rycar ( pyrifluquinanzon ) have shown effects on receptive blooms of different crop .
At a high spray charge per unit , Altus may cause some descry on opened prime of Kolanchoe . This was moreapparent on dark blooms than light . There have been no composition of effect on other crops as of yet . ( BUT , see the section below on how these trial were done ) . No phytotoxicity was seen on any of the foliage , even on youthful plants .
Rycar : The same raiser also saw effects on Kolanchoe with Rycar , but the price was worse . On the red sort , along with more severe petal streaking , it appeared that some of the unopened bud were burned . As with Altus , however , the legal injury was hold to the flowers and bud , and did not affect the foliage .
standardised damage was see lately at another raiser ’s , where a single diligence of Rycar ( at label rate ) caused austere petal streaking when put on to spread gerbera flower . In this case , the agriculturist suspected the scathe occurred because Rycar was sprayed during a sunny good afternoon . No damage was seen when the grower essay to re - make the damage on a turbid day .
Rycar has also induce issues on certain tropical plants , such as the Goldfish plant , if used repeatedly at gamy nebulizer rates . It seems to have a flora growth regular - comparable gist , have stunt flying and ramification . ( take note : I had never heard of this plant before this issue , and am now in love with it ! ! ! ) .
So far , Ference ( cyantraniliprole ) does not seem to be a high-risk chemical for aphid control . Even with repeat applications , growers are not seeing any phytotoxicity .
However , as many raiser have already been using Ference ( Exirel ) to help inhibit thrips , overutilization is a real concern , potentially resulting in the ontogenesis of resistance in thrip and aphids . Given this , Ference should be saved for aphid control , or for thrips outbreaks only ( alternatively of being used prophylactically , as I ’ve been seeing in the industry ) .
A method to test for phytotoxicityPesticide labels normally include a obscure instruction on phytotoxicity to the consequence of " always test on a low expanse to confirm tolerance prior to adoption " . But what is the best style to go about this ?
The personal effects above were learn on Kolanchoe by a grower who always does the same trial with new chemical / crop combination . His ( very wise ) feeler is to give the chemical substance at the in high spirits label rate as a " sprench " on a modest subset of plants , as a " worst - case scenario " . In his trials , he usually include vernal , vegetative plants , ripe , blossom plant with light blooms , and mature flowering plant with drear blooms .
The reasoning behind this app is to quickly guess what would befall under iterate app , or if a atomiser applicator got a little " heavy - handed " at the end of a row after a long day . If little to no phyto is see to it under this scenario , the grower can confidently apply 1 - 2 practical app of the chemical ( follow recording label rates/ max . covering ) on the whole harvest . In this case , he feels well-to-do apply at least 1 software of Altus at the high rate , but would do more tests before doing two back - to - back diligence of Altus on receptive bloom .
If he DOES see moderate to heavy phyto , he know he necessitate to either a ) go with a downhearted rate on that craw , b ) apply only 1 software or atomic number 6 ) obviate specific flora life stages . In this case , the grower would feel well-heeled doing multiple applications of Rycar on vegetative plants , but would use a unlike chemical substance if aphid were to pop up near sale , when plants are blossom .
reference : ONFloriculture
