Botrytis can have devastating deprivation during production , cargo ships , and in retail . An Integrated Pest IPM approach is necessary to carry off Botrytis successfully , and it is vital for growers to have substitute ascendancy method to habituate in rotation with antifungal agent to prevent resistance . Microbial biopesticides are an IPM tool for control disease while mitigating fungicide resistance risk . The acceptation of biopesticides in production is growing , but their variable performance under commercial conditions is still a challenge . advance in biopesticide enquiry reveal that they work well when used in combining with other scheme . Several natural compound have been found to enhance biopesticide efficacy with meaning implications for IPM .
In old AFE - funded research , they launch that chitosan reduced symptom because of Botrytis on petunia leaves . Chitosan is a rude biostimulant compound infer from chitin that has fungistatic and antimicrobic belongings . In this project , they inquire the economic consumption of commercially available chitosan production to enhance the efficaciousness of microbial biopesticides for the control of Botrytis . The objectives were to identify chitosan diligence rates for economic consumption in floriculture to avoid phytotoxicity and evaluate chitosan - biopesticide co - app to suppress Botrytis on petunia .
Since chitosan can induce phytotoxicity , commercial chitosan products were screened to identify practical program pace that are safe to use and crush Botrytis on flowers , using petunia as a model crop . Detached flowers were spray to gleam with chitosan treatments ranging from 0.1 - 0.3 % chitosan . Treatments included Tidal Grow low molecular weight ( MW ) , Tidal rise high MW , ARMOUR - Zen 15 , and a water control .
Greenhouse experimentation were conducted to name any synergistic effect of commercial chitosan product combined with biopesticides for disease quelling . Four weeks after rooting , petunia plants were sprayed to glint with the chitosan treatments ( Tidal Grow Low MW or ARMOUR - Zen at 0.3 % ) or with water and set aside to dry . Next , plant were sprayed to glisten with a biopesticide ( Cease , Howler , and Botrystop WP ) or water .
Twenty - four hours after the treatment app , fifteen leaves per treatment ( three from each plant ) were hoard and inoculated with Botrytis . Additionally , twelve peak per treatment were removed and inoculate with Botrytis . The leaves and flower were incubated for 48 hours , and disease severity was measured using a 1 - 9 disease severity scale ( Figure 1 ) .
Figure 1 . evaluation scale used to assess Botrytis rigour on Black Cherry petunia flower . percentage represent the flower area bear witness symptoms . Each flower was assigned a evaluation ( 0 - 9 ) agree to the picture it most clearly resemble . ResultsProducts prepared at 0.2 % and 0.3 % ( v / v ) chitosan mingle with a unionized surfactant CapSil ( 4oz/100gal ) sprayed on heyday provide good spray coverage with modest phytotoxicity on bloom ( Figure 2 ) .
Figure 2 . Supertunia Black Cherry efflorescence 24 hours after being spray with three commercial chitosan product at various chitosan concentration ( 0.1 – 0.3 % ) with the addition of the wetting agent CapSil ( 4 oz/100 gal ) .
As observed in previous experiments , leave from plants treat with Tidal Grow or ARMOUR - Zen alone had smaller lesions than leaf from plant treated with body of water . While there was an enhanced core of the biopesticide + chitosan treatments on reducing wound size , this was mostly due to the reduction in disease do by the chitosan intersection . Only leaves from flora treated with the Tidal Grow + Cease combination had less disease than leaves from plant treated with Tidal Grow alone or Cease alone , suggesting a genuine synergism is go on between the active ingredient of Cease and chitosan .
Disease suppressive effects and chitosan - biopesticide synergisms were more clearly watch on leaves compare to blossom . This may be because heyday are more susceptible to Botrytis , and inoculated flowers often have mellow disease rigor , regardless of discussion . However , there was a 28 % reduction in disease severity in flower treated with ARMOUR - Zen and Cease liken to flowers just treated with Cease .
The resolution can be summed up as follow , chitosan products can be implement to petunia plants during flowering at 0.2 % and 0.3 % ( v / v ) fuse with a wetting agent . Chitosan was more efficacious at reducing Botrytis compared to the biopesticides , but a synergistic effect was honour on the farewell of works treated with Tidal Grow + Cease .
The consequence from this research show that chitosan can be an effective addition to an IPM program for Botrytis direction . To see the full research report , click here .
