How Vaccinations Can Make You Think About Tomato Disease Resistance

… or better titled as “odd things that run through a horticulturist’s mind while on Facebook”.

This morning I had some down time while I was waiting for a few of my Saturday morning tasks to ‘do their thing’.  Sitting there in the kitchen, I got on my phone and looked through my Facebook feed to see what was new and interesting with people.   One of my Facebook friends had a post about how she did not understand why unvaccinated kids made vaccinated kids sick.

Of course, the scientist-that-used-to-teach-college-classes-and-believes-knowledge-is-power that is in me responded about infectivity, virulence, gene mutations, and the like.

Vaccinations do not make one 100% immune to a disease. Giving a vaccine to an individual stimulates their immune system to recognize the pathogen and develop adaptive (acquired) immunity. The adaptive immunity allows the person to have more resistance to the particular disease and reduce the risk of death should they contract it.

The reason why those without the vaccine can infect those with the vaccine comes down to the basics of resistance, pathogenicity, and genetic mutation. An unvaccinated child can increase the risk of disease for everyone that is exposed to him or her because exposure is not a “yes or no” kind of thing that is determined by if you did or didn’t get vaccinated. For the vaccinated individual, the concentration of viroid particles they are exposed to (i.e. did they walk past the infected person in a store? or did they sit next to them for hours?), the virulence of the virus strain, and their overall health (i.e. existing conditions, diet, etc.) determines if they will be able to fight off the disease with antibodies or if they will get sick.

Unlike an organism like you or I that are multicellular and complex, a virion (a single virus particle) is nucleic acid (DNA and RNA) enclosed in a capsid (a protective protein shell). They are not even as complex as a single cell and therefore not living because they require a host cell to fulfill their life cycle. Once a virion enters your body, it attaches to a particular cell that has specific components that will be needed for its replication process (usually white blood cells). Once attached, the virion penetrates the cell wall through endocytosis (energy-requiring cell absorption) and injects the nucleic acid into the host cell. The host cell replicates the nucleic acid and creates many new virus particles. The host cell bursts open and the released newly made virus partcles go attack more host cells. When an individual has had a vaccination, their body develops antibodies. Once an antibody recognizes a virion (the antigen), it attaches to the surface and destroys the virion by opsonization and the formation of a membrane attack complex.

Viruses are quite perceptive to their environment and can adapt and mutate easily. While the antibodies in a vaccinated individual can have a field day of attacking fun, the virus’s virulence and vaccinated person’s health can play major factors in the quality of the job the antibodies do. If a particular virus strain is virulent, it has mechanisms that help it to avoid the antibodies. A pyrogen fever is one of these, as the virus induces the fever to shift the body’s temperature outside of the ‘ideal’ range to reduce the ability of the antibody to function. If a virion attaches to a cell that it not the healthiest and replicates, it is possible for antigenic shift or genetic recombination to occur. Antigenic shift is where the DNA or RNA sequence is recombinated or reasserted. Genetic recombination is the process in which the DNA is broken and rejoins at the opposite ends. It occurs rampantly. By either process occurring, all new virus particles created in the host cell and in the successive host cell attacked will not be recognized by the antibodies developed through vaccination. You have now created a pandemic by a virus that is not resistant to the antibodies in everyone that has been vaccinated with that particular disease.

It’s not hype or somebody just saying it – it is true because it is well documented and can even be demonstrated by a student in any lab. I used to work with Tobacco Mosaic Virus in disease resistant and non-resistant tomatoes and Potato Virus Y and Potato Spindle Tuber Viroid on Andean potatoes that my professor brought back from her germplasm expansion trips. I easily manipulated these same principals to test resistance and give my professor parameters to use for her future breeding projects. While I’m sure people would argue that plants are a lot simpler than people, the same principles still apply because viruses, not complexity of the host organism, is the common factor.

You are not alone in thinking that vaccinated or resistant means 100% coverage – probably 75% of the tomato calls I received when I worked in the seed industry were from people calling in to grump that my company had sold them bad seed because their precious resistant tomato still caught blight. It doesn’t mean it’s perfect, just means that it can tolerate it a little bit better. Flora or fauna, disregard of science will not lead to perfection.

Further comments back and forth dealt with the logistics behind the recent outbreak of measles related to Disneyland.

I’m sure that some of her FB friends and some of mine read this and thought I was pulling out my soapbox and railing against the world on the benefits of vaccination.  Not so to the soapbox, and hopefully not so to people thinking that.  It is more a “old Mert planned to put up a sentence or two, and then her talkative nature attacked her brain and made it spew out every detail it knew on the subject because there is always background details that are important and somehow pulled plants into it just because plants thoughts are always there lurking around”.

It’s true:  plants are always on my mind. Even to the point of where I sometimes have dreams of feeding homegrown vegetables to children that live on chicken nuggets and ice cream.  And of course my comment pulled in Tobacco Mosaic Virus and various potato viruses.

Diseased Tomatoes

But, I royally digress.  This all, in a very roundabout way, it made me think of a very common question I got while working in the seed industry and here on my blog:


“Why did my disease resistant tomato catch blight/verticillium/etc. and die?”


As previously stated in a more vaccination-oriented format, resistance is not a 100% shield that goes around your plant and makes it indestructible.  It doesn’t matter if we are talking about a virus, bacteria, or fungus.

For example, lets say that you planted your Resistant Lacking Tomato next to a Big Beef VFFNTASt Hybrid Tomato.  Your Resistant Lacking Tomato will get a disease — blight, verticillium, etc. — and within a week or two your Big Beef plants has it too.  Doesn’t mean that the seed from the company you bought it from is bad. Keep in mind these are “resistant” varieties, not completely disease-proof. They can maybe hold out for longer, but are not immortal.  In areas of very high concentrations of disease organisms, the resistance may not be enough to overcome these odds.

Former customers of mine at my old unnamed workplace were always quick to point out that heirloom and open pollinated varieties where not disease resistant because they “don’t have the letters”.  Don’t let that fool you too.  Hybrids ALWAYS have the letters because the breeder/vendor that is selling it to your mailorder seed company of choice has done the testing to find out what it has the edge on.  It is a marketing tool to get you to prefer their variety over another.  Of course, the question is always what their variety was compared to in the testing…

Just because an heirloom or open pollinated variety doesn’t ‘have the letters’ doesn’t mean that they are going to keel over at the first sign of disease.  The fact of the matter is that 99% of these varieties have not been tested.  Most land-grant universities have breeding programs and heirloom testing is a matter of $$$ rather than finding a truly good, resistant plant.  First of all, most open pollinated or heirloom varieties sell wholesale for a couple dollars a pound.  Hybrid varieties sell for a LOT more than that — upwards of $100s per pound depending on what supposed resistance or other desirable traits they have.  What professor is going to do research to determine the resistance of the old heirloom seed his grandma used to grow rather than developing a new variety that can sell for a ton and earn him some nice royalities?  Um, hello — from my experience I can tell you that a lot of PhD holders are willing to sell their soul to the industry rather than do the right thing for a lot less minor things that determining disease resistance.

Back in 2010 when I was growing a trial garden for the company I worked for, I had in a bunch of new hybrids that they were thinking about including in their next catalog and about 25 varieties that were already being offered by the company but had poor catalog and internet pictures.  That year we had a horrible time with late blight because we had a very humid, warm summer.  As I watched the blight spread through the tomato patch, it was interesting to see that the first to die were not the heirlooms, but many of the hybrids!  So much for that resistance!  As the varieties still standing became a handful of names, I was left with a couple Japanese numbered hybrid varieties (which had beautiful looking fruits with the texture of moist cardboard), Matt’s Wild Cherry (heirloom) , and 3 heirloom varieties that were already in the company’s catalog.  Interestingly enough, the next year the 2 Japanese hybrid varieties and a number of the other hybrids that had died were added to the catalog.  The Matt’s Wild Cherry was not added, and 2 of the heirlooms that we had already offered that survived were cut to make room for the hybrids.  Remember, it’s all about marketing.

So, the next time you have a tomato, hybrid or otherwise, that is having disease issues in your garden, don’t blame the seed company.  Look at what you are doing in your cultural practices and learn from the experience:

1.  Grow more than one variety because there is always one that won’t get as sick as the others. Not including the varieties I grow for sale, I have 4 staple varieties that are always in my garden.

2.  Rotate your crops so your tomatoes (and other Solanaceae family members) will not be in the same spot for four years.

3.  Don’t water your garden after 4 pm in the afternoon.  Tucking your garden in bed for the night with wet feet is a perfect way to start just about any disease.

4.  When the growing season is done, clean up your garden.  As tedious as it may be, pick up every leaf, stem, fruit, etc. out of the garden.  Heap it up in a pile, dry it down, and burn it on a good winter day  or bag it up and take it to the dump/put out for garbage collection.  DO NOT COMPOST IT!  DO NOT TILL IT IN!  While people will tell you the benefits of green manure or how much your compost pile will grow by, the small ‘reward’ is not worth the trouble you will reap.  It only take one small particle of infected material to be incorporated into your soil or compost to create problems down the road.  Don’t believe me?  Ask the 1800s Irish how their practices worked… Famine much?

5.  Keep your plants healthy by giving them the care to help them grow healthy.  Water, fertilize, cultivate, trellis, etc. as needed to make your plant grow to it’s best potential.


(And 6. Your horticulturist recommends vaccinating your children using the 1981 schedule.  ;-D   )




© Mertie Mae Botanics LLC and Horticulture Talk!, 2015. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mertie Mae Botanics LLC and Horticulture Talk! with appropriate and specific direction to the original content.


7 thoughts on “How Vaccinations Can Make You Think About Tomato Disease Resistance

  1. I admit, I’ve been one of those customers. Sorry if it was your company I called in to. I usually buy from Territorial, Fedco, and Nichol’s. I never knew that, but it makes a lot of sense. I already do all the gardening practices and often get a pissed off glare from my Master Gardener neighbor across the road when I light the big pile from our acre garden up in about January and invite the guys over for a beer and bonfire. She is always trying to poke her nose into my business about how much better it would be if I compost. Yeah, then I’d be like her taking her uppity self to the garden center to buy spray all summer.

    Real men get their shots: in their arm, in a glass, and out on the range.

  2. Agree with you on the vaccinations. Even though I am a nurse, I’m not one to make a dash to the doctor for a cure-all to everything. I believe in the power of herbal medicine. However, know from treating pediatric patients that the kids that have their vaccinations are a lot healthier and recover much quicker from illnesses and procedures than the kids that have not had them. A few years ago had a little boy (old enough to have long ago received his vaccines) in that had pneumonia and was in for a few days. Was finally sent home to finish recovering. An sibling contracted whooping cough around the same time. Little boy caught it and died. Nothing you can do about it. I realize people are all worried about mercury and autism and similar things, but that doesn’t excuse poor parenting. Why let your kids knowingly suffer?

    Nice transition into the tomato diseases too. We grow heirlooms and never have problems. Some of my neighbors think I am nuts until they taste how good they are.

  3. I’ve found that to be true too with the hybrids and heirlooms I grow. I grow about 20 varieties and do all my own canning, so I always have something to pick and put up no matter what the year is like. My parents raised me without vaccinations. I had measles sometime around 5 and remember it being one of the worst times in my life. When I was 23, I got chicken pox. I nearly died because I went into convolusions. Thank goodness I had a roommate to call 911 or I wouldn’t be here. When I became a parent a few years after that, the first thing I did was look into getting vaccines for my kids. Like you, we did the 1981 plan. I’ve since been vaccinated with as many of them as I can get plus the shingles one. I’m fortunate that the other kids I went to school with had them because I probably would have been a lot sicker. I realize why my parents did what they did, and although it doesn’t make them a bad, it does make them uninformed and uneducated. After my chickpox experience and when I had my first child, my mother read a lot of the research I was looking into so I made the right decisions. So many times she said she didn’t know about various things or didn’t understand it. After reading everything, she realized she would have made a different decision if she were back in the early 80s when my brother and I were born. Just because one believes in herbal remedies or Eastern medicine doesn’t mean that you should be completely blind to innovations that can help. My parents philosophies led to my incident and my brother having years of horrible asthma because he was allergic to the lobelia he was being treated with for the asthma because my parents did not believe in inhalers. I don’t want to blame my parents, but I encourage others to really look at their medical knowledge and take the lack of it into consideration when it comes to figuring out decisions for their kiddos.

  4. My neighbor doesn’t vaccinate her kids. She doesn’t let them go to school and allows them to learn through their own creativity and interest with unschooling. Doesn’t ever let them have anything with caffeine. Other various things. They are odd enough that the family participated in the tv show Wife Swap. I don’t want to say this about all people that raise their kids like that, but my neighbor’s kids are some the dumbest, dirtiest, rotten acting, sickliest kids you have ever seen. Just more kids to grow up and be a financial burden on the government and taxpayers. Makes me want to throw my rotten garden produce at them.

  5. So I don’t know if your friend is anti vaccines or just never had a high school science class yet, but I’m hoping it’s because she is a kid/teen and still has schooling to go. As for me and my partner, we eat all organic and natural vegan foods and try to stick with home remedies for colds and flu. But when one of the kids gets sicker than normal, they go to the doctor and get medicine. Why play Russian roulette with your kids? I know that a lot of people like to blame some kind of conspiracy theory for why they don’t go to the doctor or get shots or eat food with GMOs, but most of those people seem to have a basic lack of education that prevents them from using their noodle to think aboutthe situation and react logically. Your article is a great example of someone who has either learn rational thinking through education or by researching the topic with reliable resources. Vaccines are not the devil. Fears from old wives tales is.

  6. If I am reading the article right, 42 of the people didn’t get their shots and 9 did? Is this what your friend was looking at? What’s not to understand? Thanks for the throwback Saturday to my microbiology class back in college.

    Is Seed Savers or similar groups doing anything to test disease resistance in their tomatoes? Seems like something they’d be all over it.

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