Tuesday, 5 June 2012

Deciding on a Foliar Fungicide

Fungicides are options for all growers crop input arsenal. There are a number of stages where fungicides are generally applied, typically targeting different diseases, especially in cereals. Determining when is the best time to spray can be difficult, but you need to identify the main disease you are going for. With fungicides typically being in short supply, it is best to make a decision early and book the product you need at your local retailer.
I am going to start off talking about pulses. When it comes to pulses, the 2 main time when you will apply a fungicide is with your herbicide, typically something like Headline from BASF is sprayed if there are any fungicides applied with herbicides in pulses. This is to keep diseases like ascochyta slowed down until flowering when you can go in with another fungicide application. If using a product strobilurin fungicide you will also see some plant health benefits that include increased N use efficiency, water use efficiency, decreased ethylene production and a grocery list of other benefits. The next time that is typical for a fungicide application is from beginning of flowering up until about 50% flower, under high disease years there may be a need for other application beyond this stage. Products like Quadris (azoxystrobin) from Syngenta and Headline (pyraclastrobin) from BASF are very good options for ascochyta, if anthracnose is what you’re after then Quilt (azoxystrobin and propconizole) from Syngenta and Headline again are very good options. (Note: Quilt isn’t registered on ascochyta, but I have seen it do a relatively good job at holding the disease back in lentil). If you are concerned about Botrytis and sclerotinia (white mould) then Lance (boscalid) from BASF is a great option, or you can go for the heavy hitter fungicide Headline DUO which is Headline and Lance and get a whole spectrum of pulse diseases. If you are strictly going for sclerotinia then Lance is your soul registered option in lentils, or peas, but in a crop like Beans you have options such as Allegro from Syngenta. There is Serenade (bacillus subtilis) , a bio fungicide from UAP as well.  In the coming years there looks to be a couple new options becoming available from companies like Bayer and BASF that are apart of group 7 fungicide class (SDHI’s) that are looking very promising.
Note: There are some other fungicides for pulses out there such as Proline (prothioconazole) from Bayer, but is used in limited amounts on pulses due to its lack of activity on a number of diseases and price.
When it comes to canola the first option you have for a fungicide is to hit it with your incrop with a full rate of Headline. This is going to decrease blackleg infestations as well as give the plant some added health benefits as discussed earlier. When it comes to 20%-50% flower this is the time you are going to be aiming for control of sclerotinia. There are a number of products out there to help combat this disease, they include; Proline, Astound (cyprodinil,fludioxinil) from Syngenta, Lance, Quadris, Rovral (iprodione) and Serenade. The products that are used most in my experience tend to be Proline and Lance. Astound is a newer product, but shows potential, especially if you do any reading on 3rd part research on the disease and fungicide controls. There is a new option this year from Dupont called Vertisan (penthiopyrad) which may be an option for you to try as well. Most of these products will do a good job, it may come down to what you feel comfortable with, fits into your programming or is easiest to get your hands on. Doing side by side trials is a great option to see which one works best for you.
Wheat is the tricky one. The first option you have again is at in crop timing to tank mix Tilt (propiconazole) with your herbicide. These typically can give you a good start on decreasing leaf disease levels if there is an early infestation, especially if you are later spraying your crop (5 or 6 leaf). I have read some research showing half rate Tilt had very little difference in efficacy vs full rate. This typically will give you 7-14 days protection. Spraying a product like Stratego (trifloxystrobin and propiconazole) from Bayer with your in crop herbicide can cause it to heat up the herbicide and cause crop damage, this is due to the strobilurin portion, watch spraying any strobilurins with your herbicide tank mixes. The next time to spray a fungicide on cerals is flag leaf stage. The flag leaf and penultimate leaf can combine to contribute for upwards of 70% of total yield, so protection of these 2 leaves is very important. If you are trying to control a disease such as stripe rust then there are a number of options including Folicur (tebuconazole) from Bayer which has very strong activity on rust, Caramba (metconazole)which is also strong on rust and Quilt which is strong on rust as well and provides increased length of protection as well as some better systemicity. The new Twinline fungicide from BASF is a combination of Headline and Caramba and should offer very good activity on rust as well as on other leaf diseases. If you are simply trying to control septoria, tan spot, spot blotch etc. then there are a number of options including all the fungicides I have stated previously. Products like Quilt and Headline are going to have some added plant health benefits due to the family of fungicide they are, so good to take that into account as well. When it comes to fusarium headblight control in my eyes the top two products are Prosaro (tebuconazole and prothioconazole) from Bayer and Caramba. The group 3 triazole family of fungicides has very good activity on fusarium species diseases. Both of these products are very good, in my research there are slight differences though. Prosaro has 2 ingredients, one which is faster acting (tebuconazole) and one which provides longer control (prothioconazole). The research I have done consistently shows that Prosaro has the slight edge in actual suppression of the disease, while Caramba has the slight edge in actual DON levels on the kernels (DON is the mycotoxin produced by FHB infection) based on the fact it is better at decreasing colonization of the bacteria that produce the mycotoxin. Leaf disease is strong with these products as well.
Choosing a fungicide can be tough, but go in and ask questions about your specific situation at your local retail and they should be able to give you the answers you need to make an informed decision.
I didn’t break down every fungicide in depth as I would have liked, but if you have any questions on specific ones feel free to ask and I should be able to give you some information to help.