Tag Archives: efficacy

agriculture

Biopesticides for tomato bacterial diseases: On-farm demos

row of tomato plants with some green fruit and a sign that says Double Nickel 1 qt/A alt. Kocide
On-farm demonstration of reducing copper applications by alternating with biopesticides to protect against tomato bacterial diseases.

Last summer I wrote about integrated pest management strategies (IPM) for tomato bacterial diseases and how biopesticides fit into strategies for managing these diseases. You’ll recall that research trials conducted at Cornell in Chris Smart’s lab indicated that you could replace some copper sprays with the biopesticides Double Nickel or LifeGard and achieve the same level of control of tomato bacterial diseases. In 2023, we wanted to demonstrate what this might look like on vegetable farms around New York State – Long Island, eastern NY, and western NY. Here’s what we observed.

 

Results from On-Farm Demos

Biopesticides are not a panacea for tomato bacterial disease problems. When disease pressure is severe and weather is favorable, bacterial diseases can be difficult to manage, even with copper-based fungicides. Canker is especially difficult to manage because the bacteria that cause the disease move systemically within the plant. Successful management of bacterial diseases in tomatoes requires the use of multiple IPM tools, including starting with clean seed and healthy transplants, and using new (or effectively disinfected) tomato stakes.

On farms that experienced tomato bacterial disease outbreaks, adding Double Nickel did not satisfactorily control bacterial disease. These farms had very uneven distribution of tomato bacterial canker across the fields, complicating comparisons between the Double Nickel alt. copper treatments and the copper only treatments. Two farms (in western NY) saw slight to moderate increases in fruit quality when they added Double Nickel sprays in between copper applications compared to applying copper every 10-14 days. This resulted in estimated 2% and 37% increases in fruit value, corresponding to an extra $19 (from nine harvests) or $72 (from four harvests) from 100 row feet of tomatoes. However, the Double Nickel sprays were in addition to copper sprays, not replacing them. We don’t know if applying copper every 7-10 days would have resulted in better disease control. On the third farm, we saw no benefit of replacing half of the copper applications with Double Nickel.

The two cooperating Long Island farms saw no bacterial disease in 2023. But replacing half of the copper applications with either Double Nickel or LifeGard still seemed to have economic advantages. We estimate that the value of their crops increased by 7% and 59%, or $244 and $1,617 per 100 row feet of tomatoes harvested four times. Note that the price for fresh tomatoes on Long Island is high compared to some other markets in NY. We used $5-$6/lb in our Long Island estimates. Also, we don’t know what would have happened if there had been a bacterial disease outbreak on these farms.

On all cooperating farms, we collected data on very small sections of the field (10-40 row feet of tomatoes). Estimated potential impacts on yield over much larger areas should be taken with a grain of salt.

Green Roma tomato fruit with both white spray residue and classic fruit symptoms of tomato bacterial canker – brown spots with a white ring around them
Tomato bacterial canker is a difficult disease to manage, even with weekly copper applications. Use of multiple integrated pest management (IPM) tools yields the best results. Photo credit: Crystal Stewart-Courtens.

 

Economics

We researched some prices for pesticides from a few different suppliers. Below are the assumptions we made to calculate some price estimates and make comparisons among some biopesticides and copper pesticides. Prices for pesticides can vary across regions and time. If you think any of these numbers are far out of line, please let Amara know!

If you are applying… and a container costs you… and you apply at a rate of… Your cost per A per application is:
Actinovate AG $115/18 oz bag 7.5 oz/A (range on label is 3-12 oz) $48.00
Double Nickel LC $85.25/1 gal 1 qt/A (recommended for tomato bacterial diseases) $21.31
LifeGard WG $148/1 lb bag 4.5 oz/100 gal and 50 gal/A = 2.25 oz/A $20.80
copper (Kocide 3000-O or Badge X2) $102/10 lb bag 1.25 lb Kocide, 1.8 lb Badge X2 (highest rate on label) $15.00
copper (Badge SC) $150/2.5 gal 1.8 pt/A (highest rate on label) $13.58
Copper (Champ Formula 2 Flowable) $139.95/2.5 gal 1.33 pt/A $9.31
copper (Cueva) $114/2.5 gal 1 gal/A (label rate is 0.5-2 gal) $46.27

As you can see, the biopesticides in the table range from fairly similar in price (Double Nickel and LifeGard) to approximately 5 times the cost of the less expensive coppers (Actinovate). Each copper application replaced with either Double Nickel or LifeGard is estimated to increase the pesticide cost by $6-$12 per acre per application. If a grower makes eight applications in a season to protect tomatoes from bacterial diseases, this would be an increase of $24-$48 per acre for the season if half of the copper applications are replaced with Double Nickel or LifeGard. If a grower adds LifeGard or Double Nickel applications to a 14-day copper spray program, the cost increase is greater. Purchasing product for four additional applications costs an extra $84 per acre, not including other costs of making more applications, like fuel, labor, equipment depreciation, etc.

 

Protecting people and the environment

Replacing some copper sprays with biopesticides can have other benefits. For example, the following table compares restricted entry intervals (REIs), label signal words, and field use ecological Environmental Impact Quotient (EIQ) for several biopesticides and copper formulations. Shorter REIs indicate a pesticide has lower toxicity to agricultural workers. The signal word shows the relative acute toxicity of the pesticide to the pesticide applicator.

 

Product Active Ingredient (%) Rate REI Signal word Field Use Ecological EIQ1
Actinovate AG Streptomyces lydicus WYEC 108 (0.037%) 12 oz/A 4 hrs Caution NA
Double Nickel LC Bacillus amyloliquefaciens strain D747 (98.85%) 1 qt/A 4 hrs none on label NA
LifeGard WG Bacillus mycoides isolate J (40%) 4.5 oz/A 4 hrs Caution NA
Serenade Opti2 Bacillus subtilis QST 713 (26.2%) 20 oz/A 4 hrs Caution 7.2
Badge SC copper hydroxide (15.36%); copper oxychloride (16.81%)3 1.8 pt/A 48 hrs Caution 40.1
Champ Formula 2 Flowable copper hydroxide (37.5%) 1.33 pt/A 48 hrs Warning 34.5
Cueva copper octanoate (10%) 2 gal/A 4 hrs Caution NA
Kocide 3000-O copper hydroxide (46.1%) 1.25 lb/A 48 hrs Caution 38.2
MasterCop copper sulfate pentahydrate (21.46%) 2 pt/A 48 hrs Danger 66.4

1 The Environmental Impact Quotient (EIQ) seeks to quantify the environmental impacts of pesticides. Higher numbers indicate more negative impacts. The values reported here are “field use” values, calculated based on the rates listed in the table. These values vary depending on how much product you use per acre. The ecological component summarizes risk to fish, birds, bees, and beneficial insects.

2 The active ingredient in Serenade Opti is in the EIQ database, while the active ingredients of the other biopesticides in this table are not. The EIQ for Serenade Opti is expected to be similar to those of Double Nickel and LifeGard because they have similar active ingredients. It may also be similar to the EIQ for Actinovate.

3 Only copper hydroxide – not copper oxychloride – was in the EIQ database, so this ecological EIQ was calculated using 32.17% copper hydroxide (sum of the percentages of the two active ingredients).

 

Other benefits of reducing copper applications on a farm could include:

  • It reduces the risk of selecting for tomato bacterial pathogens that are resistant to copper.
  • Many copper fungicides leave a visible residue on fruit, which may impact marketability if applied close to harvest.

 

Update on labels

In last summer’s post we noted that neither Double Nickel nor LifeGard included tomato bacterial canker on their labels. In New York State, formulations of these biopesticides now have 2(ee) labels that include this disease on tomatoes. Make sure you have a copy of both the original label and the 2(ee) label in your possession if you are using these products for tomato bacterial canker in NY. If you are in NY, you can find these and other labels through NYSPAD.

 

The Bottom Line

  • It is very important to use all your IPM tools for tomato bacterial disease management, especially for canker. If you are bringing canker to your field in seedlings or on tomato stakes, it will be very difficult to catch up with the disease using any pesticide if weather conditions favor disease.
  • Some biopesticides are competitively priced (per bottle and per acre) with copper formulations. Replacing a few copper applications with these products will not cost you much more.
  • Replacing some copper applications with biopesticides offers some additional benefits, including copper resistance management, and potentially reduced risk to the environment and human health.

 

 

Changes in pesticide registrations occur constantly and human errors are possible. Read the label before applying any pesticide. The label is the law. No endorsement of companies is made or implied.

 

This post was written by Amara Dunn-Silver, Biocontrol Specialist with the NYSIPM program. Thanks to collaborators Chris Smart, Professor in the School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section at Cornell University, Crystal Stewart-Courtens, Extension Vegetable Specialist, Eastern NY Commercial Horticulture Program; Elizabeth Buck, Cornell Vegetable Program; Margaret McGrath, Retired Faculty, School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section at Cornell University, and Sandra Menasha, Cornell Cooperative Extension, Suffolk County. Support for this project was provided by the NY Farm Viability Institute.

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Managing tomato bacterial diseases? Biopesticides could help

Are you using copper to protect your tomatoes from bacterial diseases? Research from Cornell suggests that you could replace some of those copper applications with a biopesticide.

Two pictures of tomato leaves showing small brown specks, and larger specks or groups of specks surrounded by yellow margins
On tomatoes bacterial speck and spot both look like small black spots which may develop yellow halos around them as the lesions age.

Preventing bacterial diseases on your tomatoes starts with good integrated pest management practices.

  • > 3-year rotation out of tomatoes and peppers
  • Clean seed or disease-free transplants
  • Heat treat seed (unless it is pelleted or treated)
  • Good sanitation in transplant production facility (e.g., new flats or sanitize between uses, sanitize greenhouse after each season)
  • Inspect transplants and destroy any with symptoms of bacterial disease
  • Do not work in tomatoes (e.g., tie, prune) when leaves are wet
  • Either sanitize tomato stakes between growing seasons, or use new stakes each year (preferred)
  • If you have an outbreak, till in plant debris quickly.
Green tomato fruit held in a white person’s hand with four black and brown spots, each surrounded by a white halo
Bacterial canker lesions on tomato fruit

If you are doing all of these things and still need some extra protection from bacterial diseases (e.g., in a wet growing season), pesticides might also be in your IPM toolbox.

In New York, we’re fortunate that so far few bacterial isolates have been found to be resistant to copper. Copper resistance is a major problem in the southern U.S. and we’d certainly like to preserve its efficacy here in NY. Some people are also understandably concerned about the environmental impacts of using a lot of copper on their farms.

Cornell vegetable research programs led by Chris Smart and Meg McGrath have been testing products against our three bacterial diseases – spot (Xanthomonas), speck (Pseudomonas) and canker (Clavibacter) for a number of years. So far, two products – Double Nickel LC (1 qt/A recommended) and LifeGard (4.5 oz/100 gal water) – have been rising to the top. When comparing these products alone to alternating either with copper, both worked better as replacements for some copper sprays than alone. Some research trials only included the biopesticide by itself, but the Double Nickel label states that it should be applied only tank mixed or rotated with copper-based fungicides.

Double Nickel alone (one year of data in Geneva) was as good as copper against bacterial spot. Double Nickel alone (two years of data in Geneva) and LifeGard alternated with copper (one year on Long Island) were as good as copper against bacterial speck. While neither product is registered (legal) for use against tomato canker, in research trials in Geneva, Double Nickel (one year) and LifeGard (two years) alternated with copper controlled canker as well as copper alone. So if you are replacing some copper sprays with either Double Nickel or LifeGard, you’ll likely notice some incidental bacterial canker protection, too.

New to using biopesticides? The New York State IPM Program has a new resource to help. Biopesticide profiles (scroll to bottom of page) for Double Nickel, LifeGard, and seven other products provide information on tank mix compatibility, shelf life, and other practical tips.

Screen shot of a website section entitled Biopesticide Profiles. PDFs of these profiles are available for Actinovate, Contans WG, Double Nickel, LifeGard, Regalia, Serifel, Stargus, Theia, and Timorex ACT
Follow the link in the text and scroll to the bottom of the page to find these biopesticide profiles from the NYSIPM program.

Changes in pesticide registrations occur constantly and human errors are possible. Read the label before applying any pesticide. The label is the law. No endorsement of companies is made or implied.

 

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program, and Chris Smart, Professor in the School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section at Cornell University. Support for this project was provided by the NY Farm Viability Institute.

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Which biopesticides work? Updated resources

A caterpillar eats or comes in contact with a bioinsecticide that causes the caterpillar to stop feeding.
Some bioinsecticides cause insect and mite pests to lose their appetites. Depending on the bioinsecticide, it either needs to contact the pest or be eaten by it.

Biological pesticides (biopesticides) are pesticides with active ingredients that are considered natural. According to the EPA they “include naturally occurring substances…microorganisms that control pests…and pesticidal substances produced by plants containing added genetic material.” This last category is more often recognized as certain (but not all) genetically modified organisms (GMOs). The “naturally occurring substances” (plant extracts, some natural chemicals) and microorganisms (bacteria, fungi, viruses) are the focus of today’s post. There’s a deeper dive into how biopesticides work in another blog post.

Biopesticides can be an important tool for integrated pest management because some of them may pose less risk to people or the environment than some conventional chemical pesticides. (But always read and follow the label on biopesticides to ensure you are minimizing risks!)

If you are considering using a biopesticide as part of your IPM program, you will of course want to know whether or not it is effective against a particular pest on a particular crop. A few years ago I wrote a post about efficacy of biocontrol. With some great help, I’ve been collecting summaries of efficacy trials on biopesticides conducted by universities. These summaries are available as downloadable Microsoft Excel spreadsheets for the following crops:

  • Berries
  • Field crops
  • Grapes
  • Greenhouse, nursery, and ornamental crops
  • Hemp
  • Hops
  • Tree fruit

The Cornell Vegetables website has some excellent information about biopesticides for vegetable diseases.

Green leaf with blue rectangles with smiling faces representing microbes as natural enemies of the pest microbes (yellow rectangles with shocked faces). The blue microbes are producing blue droplets (representing antimicrobial compounds).
Microbes used to control pests are biopesticides. In this conceptual diagram, the happy blue microbes are producing antimicrobial compounds that are killing the plant pathogens (represented by yellow rectangles with shocked faces).

Once you download a spreadsheet, take a look at the ‘Notes’ sheet for some important background information, then look at the data on either the ‘Diseases’ or the ‘Arthropods’ (insects and mites) sheet. You can sort the data on either sheet by crop, pest name, name of the product, active ingredient, or other column headings. I’ve included both a simple rating of efficacy (-, +/-, +, ++), and a numerical summary that shows how much each product improved control compared to doing nothing to control the pest.

The spreadsheets do indicate whether each product was registered in New York State at the time the sheet was last reviewed. Remember that you must confirm that the product you want to use is currently registered in New York, and that the label includes your setting, crop, and pest. You can check for current registration and download NYS pesticide labels from NYSPAD.

If you are not able to open an Excel spreadsheet, please let me know and I’m happy to get you the info in a format that works for you.

 

This work is supported by NYS Departments of Environmental Conservation and Agriculture and Markets, as well as the National Institute of Food and Agriculture, Crop Protection and Pest Management Extension Implementation Program, award number 2021-70006-35672.

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program.