Why Are My Tomatoes Not Ripening, and Billbugs

Taun Beddes 0:07

Hello, and welcome back to the homegrown horticulture podcast. I am with Savannah Peterson again this week and apologies for not uploading a podcast last week, Schedules wouldn't allow it. This week we're going to be talking about Bill bugs and what they do to lawns and how to find damage. And Savannah, what's your other topic?

Savannah 0:27

Why are my tomatoes not ripening? We've been getting some questions about that.

Yeah, so it is a beetle in the member of the snout nose beetle family. So if you've heard of weevils, these are pretty closely related. They overwinter as adults and then emerge in the spring as temperatures start to warm up and lay their eggs in the crown of grasses. Usually, they're more problems for cool season grasses like Kentucky Blue Grass less often and warm season grasses. They're a decent sized problem here because we mostly grow cool season grasses. The larval stages are the ones that cause the most damage they get into the crown of the plant. They can move around through the stems and then even down into the thatch layer. They look kind of like white grubs, but one way to tell them apart is that bill bug larva do not have legs. They just are very grumpy.

Taun Beddes 1:32

They look like little wormy caterpillars usually what a third to maybe half inch long.

Savannah 1:37

Yeah. But the white grub larva have little teeny tiny legs on them. So that's one way to tell those apart. Some things you can look for to know if build bikes are the things that are causing your lawn problems are you can gently pull on your grass and if it comes up really easily, especially right at the base of the stem, then that's that's one indicator. You can check physically look in your lawn, pull up some grass, and look to see if you can see any of them. More commonly could check for some frass in the thatch layer that looks like sawdust. And then the other one would be hollowed out stems of the grass blades.

Taun Beddes 2:22

If you took a call from a resident here in Utah County saying I think I have Kentucky Bluegrass bill bugs, how do I check for them? What would be the process?

Savannah 2:35

those

Those would be the things I'd recommend pull on the grass, look for the bugs actually in the grass. And then check those other symptoms like the frass and attach and the hollow stems. The problem is that sometimes the damage they do can be confused for other things like drought, or fungus or white grub damage. And another problem is that it can look like drought stress, but also drought stress can make bill bugs more common. So they're more likely to cause problems in your grass if your grass is already stressed.

Taun Beddes 3:08

So the bill bugs are problematic in it sounds like an overly maintained turf. I've noticed that people that fertilize you especially four or five times a year they cut their lawn really short. And then try to compensate with too much water that stresses the turf also. And so those grubs are more likely to get into those lawns and so I get calls from people all the time and they will say, "my neighbor's got cars on blocks and they barely water and mow and their lawns perfectly green and mine is just riddled with grubs. Why?" And then you try to explain Well, you're overly maintaining it. And you've made it unhealthy by trying to make it healthy and those grubs are in there. Because you've turned it into ice cream for the grubs pretty much. So one of the problems we run into is that people always want to just jump right to chemicals, what can I put on my lawn to get rid of them to where there's a lot that's important to make your lawn less attractive to them. And so what are some things that you recommend to folks to call the office.

Savannah 4:17

Correct fertilization, so fertilizing the right amount and at the right times of year following the instructions on those lawn fertilizers to the letter then watering correctly. The current drought recommendations are actually really good for controlling bill bugs because if you let your lawn dry out between waterings So currently, I think the state recommendations are twice a week for 20 minutes. If you have pop ups in 40 minutes for rotary sprinklers. And then the days in between when you're not watering, the soil dries out pretty well and those eggs that the adults lay will desiccate and so the they won't survive.

won't become larva won't become a problem. And then the other one you can do is raise your mowing height a little. I think that recommendation is about three and a half inches. And that'll also help keep that build like population down.

Taun Beddes 5:14

Some other things I've noticed is the bill bugs are less likely to get into ryegrass and fescue. They still can, but they they get their name because Kentucky Bluegrass is where they prefer to feed. And so if you have alternative lawns, you're going to be at least slightly less likely to get them as far as using different lawn grasses. The next thing we should get into is how to treat and one thing I've noticed is we'll start to get calls in July, and people's Is there anything I can dump on my lawn as far as a chemical that will get rid of them? And the answer's no. Because by this time, the grubs are pretty big and they've gone deeper into the soil. And through July, they turn into a pupa. They go dormant, kind of like a butterfly in a chrysalis. And then they merge sometime in August as adults and they do far less damage to your lawn. And so because the damage sometimes can be residual, and it may not show up for seven to 10 days after they're done feeding because the grass just doesn't immediately die, then it's just too late to start treating in July. So what's the timing that you found that is ideal for trading for the lawn grubs. If you're using a preventative

Savannah 6:29

sometime in May to early June.

Taun Beddes 6:31

So and products you would use include there's many of them out there, but they'll say lawn grub preventative and oftentimes they'll be season long. So imidicloprid a clothianodin, are a couple of them that are available local garden centers and farm stores. Some of these, like the imidicloprid may need to be reapplied in July if you're fighting other insects, such as sod web worm. But mainly the time to control these grubs is in June when they're first hatching, because they're up in the soil higher in the grass themselves. And it's just easier to get them exposed to the poison that you put down to get after them. Now you'd mentioned that there's some other insects out there, you already mentioned white grubs, that can be problematic. Fortunately, the treatments about the same. The other one that we get here commonly is sod web worm and the preventives that you would put down for Kentucky Bluegrass billbug also go after the sod web worm. But there's a number of other treatments out there that are fairly inexpensive, that will also treat those that you can pick up from local garden centers. The next topic I wanted to bring up is why tomatoes aren't ripening this year. And we get lots of calls every July and early August saying my tomatoes aren't ripening they never will. It's the apocalypse. And this year, we've been so hot that there might be some justification for people saying my tomatoes aren't ripening because it's true. So what's been going on?

Savannah 8:09

So tomatoes ripening depend on a couple of factors. The big three would be temperature, age, and ethylene production. It is this cool little hormone that I'll talk more about in a second. But the biggest factor for us right now is the temperature. We found some different sources that said slightly different things. But generally, tomatoes will slow their ripening process at temperatures that are above 85 degrees. What were what were some of the temperatures you found?

Taun Beddes 8:40

I read around 90, but it's probably you know, this research isn't performed on all tomatoes. And so you know, there could be some variety differences that some tomatoes stop or slow down at 85 and others around 90, I read one source that's had 95. So all we can really say is that above 85 to 90, you really start to get some bad stuff going on.

Savannah 9:05

And either way, we've had consistent temperatures above 90, hovering around 93 where I'm from, but a lot of the problem that happens here is that the tomato plants when they get stressed any plant really it'll start to go more into survival mode and put less energy into developing its fruit. So when the tomatoes are subject to heat or drought stress, they'll put less effort into their tomatoes. When we see these temperatures above 85 degrees, especially these two pigments that are the nice red color we like to see in our tomatoes. They're called lycopene and carotene. They stopped being produced by the plant and so we just won't be able to see any color change. The tomatoes will still start to get a little more sugar and water put into them but it's substantially less and they won't Be able to ripen on the vine when it's that hot outside.

Taun Beddes: 10:03

So one thing I read that I thought was really interesting, the temperatures above 100, the tomato development can almost completely stop. And so you'll have tomatoes that are halfway or three quarters of the way ready, and they just stay green. And if you're consistently above 100, they may not ripen very quickly or at all until temperatures cool down.

Savannah: 10:28

One hard thing there though, is that we do have a stage and tomatoes called mature green, where they are pretty much ready to go. We all like vine ripened tomatoes, but in this heat, we just can't get that nice red color. But at the mature green stage, if you take them inside where the temperatures are a little cooler and more consistent, they will be able to ripen to that nice red color without losing a lot of the flavor like you can sometimes find in store about tomatoes that were picked a little early. At the mature green stage, the plant has started to kind of wall off the fruit, so it's not getting as much sugar water anymore, but it is ready to go. So one way you can tell the difference between those underdeveloped tomatoes that are just going to stay green, and the mature green stage that's ready to pick is to just press lightly on the bottom of the tomato. And it should be pretty soft on mature green tomato, well it will all be pretty consistently more firm on an under ripe tomato.

Taun Beddes: 11:31

That's great advice. The other thing I've noticed it's more expensive. But I've noticed that a lot of commercial growers and serious hobbyists have started using shade cloth and you can buy the shade cloth in different grades. The one that we found best through research for Utah or the two somewhere around a 20 to 30% shade. And so if you've ever seen gardeners that use the little hoops in their garden early in the season, with either a plastic cover or a cloth cover, you would use the same thing for the shade. And what this will do is reduce the temperature underneath sometimes by five or six degrees. And you will oftentimes increase your yields and get the yield earlier so that I know one commercial grower that got tomatoes consistently about a month earlier than normal by using the shade cloth. And so if you have a lot of tomatoes, and you can them, it may be worth covering at least a section and what that will do is extend your tomato season out and make it so you're not inundated with all the tomatoes at once if you have one variety so that some of them ripen two or three weeks ahead of the others in the garden.

Savannah: 12:42

Just since he brought up the shade cloth I wanted to mention a little myth that I've been seeing float around and got a couple people calling in about was we do associate I think red tomatoes with a lot of sunshine because it's nice and hot and sunny outside when we usually harvest them. But sun exposure pretty much has nothing to do with tomato ripening. So I've seen some people trying things like pulling off the leaves that are right next to the tomatoes, but what that's gonna do is not ripen your tomato any quicker. It's just going to make it more susceptible to things like sunburn. And it'll just increase the temperature so your tomato will ripen even slower. So that is not the way to go. If anything do like Tom said add shade cloth.

Taun Beddes: 13:25

So that is the way to go. And along those lines, I've seen people think that their tomatoes will ripen sooner if they sever the roots. And to get those tomatoes ripe you want as many roots as you can get. And you want as much leaf canopy through the growing season. And when you hear about people taking leaves off plants, it's at the end of the season, when they're about ready to be pulled up anyway. And it's just a management technique that you should not be doing in August. The other thing I will mention on this with shade is that if you've ever noticed especially indeterminate tomatoes like celebrity, the first tomatoes you get are on the inside of the plant where it shady. And so if you pull those leaves off that will delay as Savannah said.

Savannah: 14:09

And one other just fun little fact that I was reading about today. That hormone ethylene I mentioned is the thing that's responsible for ripening of fruit and then eventually dropping it off of the plant. And if you expose fruit that aren't quite as ripe as you want them to be to ethylene sources, they'll ripen quicker and some of the common things that you have that are ethylene producers are apples, pears and bananas those things. If you've noticed if you leave them out on the counter, especially bananas will ripen pretty quickly. So if you grab your mature green tomatoes and put them inside on your counter next to your bananas or apples, they'll ripen even quicker, which is just a fun little tip.

Taun Beddes: 14:51

I wanted to mention something really quick on flower development. Those same temperatures that can slow down the tomato From actually ripening actually can fool with the flowers too. And at temperatures above 90 to 95 depending on the variety of tomato, you can actually have the flowers. cineastes offer itself a board because of the hot temperatures and so that is another reason that you may see a lack of fruit development. Because of those hotter temperatures, the flowers will fall off the plant and won't be pollinated. So another thing for using shade or not removing the foliage so that inside the planet's cooler, and you can get those flowers pollinated.

The homegrown horticulture Podcast is a production of Utah State University Extension. Show music was written by Savannah Peterson, a talented Utah State University Extension Horticulturist and the musician. Thank you again for listening

Transcribed by https://otter.ai