A couple weeks ago it was very hot with several consecutive days approaching about 100 some days 100+.
Fruit sales were poor and we didn’t get all the fruit off the vines. Now, a couple weeks later lots of plants have significant die back, and fruit size went from very large to very small. These plants are regularly sprayed with fungicides, so I don’t think it has a whole lot to do with fungal diseases. These are indeterminate varieties, btw.
Of course it’s normal to have a reduction in fruit size late in the season, but this occurred almost overnight.
I’ve been told that fruit dying on the vine sends a signal to the plant to quit producing (or slow production) but does it also signal the plant to reduce fruit size, or cause die back?
@Fusion_power@fruitnut any thoughts? Anyone have any thoughts. I’ve not been able to quickly find anything in the literature, since almost all commercial growers are growing determinate varieties, or removing all the fruit as it ripens (and not letting the fruit rot on the vine).
I’m not sure but I’d think it’s just the excessive heat not the dead/rotting fruit that’s causing issues. It’s late in the year and that’s awfully hot for tomatoes. Others are way more into tomatoes than I am. Maybe they can help.
fruitnut is on the right track. Heat Stress along with high fruit load signals the plant to reduce production by less flowering and smaller fruit. I’ve seen this with Big Beef and several other indeterminate hybrids. You can mitigate by extra watering during high heat.
Can you post some pictures of the plant. Typically the plant will drop the fruit when its overripe. Even heat loving plants such as peppers, squash, tomatoes don’t flower when temps are 100F consistently (even couple of days), exception is okra and sweet potatoes and to some extent egg plants.
I’d blame it on the high heat. Were they stressed for water during that time? I don’t think it matters to leave a tomato on the vine too long. Other plants such as cucumbers,peppers and squash left on the vine too long will slow down new production.
First question, is it possibly a nematode problem? Can you check roots to see? High temps put nematodes in high gear and they often cause problems such as described.
But I’ve not hearing any comments about negatives to leaving tomatoes rotting on the vines. Aren’t there some negatives to that? Could that have any influence in what we are seeing in the tomato rows? Is there any evidence that letting tomatoes rot on the vines reduces future production in indeterminate vines?
We spent about 4 man hours today and a couple yesterday, clearing off all the rotted tomatoes off a couple rows, just to see if it makes a difference.
Maybe I’ll try to get a few pics tomorrow, if I get some time.
Anyway, thanks for all the comments so far. Much appreciated.
I’ve noticed the same thing. I don’t think it’s high temperature related. We had two weeks of cool cloudy weather with nights low 60s and days low to upper 70s and now high 80s and low 90s for a few days.
I leave tomatoes on all the time. High heat stops pollination. Flowers can drop when temps reach 85 F. Flowers have a 50 hour window to be pollinated. The plant uses energy to survive and will abort flowers. Often running out of energy and could die back too. You’re seeing the abortion of feeding the fruits so they stay small.
It’s not just day temps if above 70 at night that can harm plants too.
Heirlooms and hybrids that can tolerate the heat better are around. Don Shorr host of the Davis Garden show knows a lot about this subject. His knowledge is amazing. He also owns a nursery and can tell you the formal name of any plant and spell it for you too. In a league of his own. My info comes from him. He takes questions for his podcast. Rarely is my gardening anything like Dons in Davis CA but we do overlap on some things and I have asked him a few questions in the past and he answered them on the podcast. Bet he has a list of cultivars that grow in higher heat.
The first pic didn’t load right. Do the tomatoes have brown spots? Could be late blight. Was it wet there? Look up late blight for more info.
Looks too extensive for just the heat.
There’s 4 varieties. Pink Girl (excellent quality tomato with high production and good size) Big Boy, Big Beef, and Supersonic.
I’m not sure how to check for nematode damage? I know we don’t get nematodes this far north in our heavy clay soil with peaches. Maybe tomatoes are different?
The tomato fruits themselves look pretty much perfect. It’s been very dry the last few weeks.
Maybe it is disease. We have had an issue with early blight in the past. I we had it under control the past couple years with our fungicide program, but maybe it’s coming back. It looks a little like early blight, but it’s just strange it seemed to come on so fast.
What fungicides? and how often applied? Damage shown could be several different pathogens. Late blight is the most likely. I’m going to suggest trialing a few new varieties.
Bella Rosa - heat tolerant, highly productive, very good flavor, but no late blight tolerance
Big Beef Plus - new release, very productive, very good flavor, no late blight tolerance
Mountaineer Delight - red, good flavor, excellent disease tolerance including late blight, also Mountaineer Pride
Checking for nematodes is simple. Pull up a couple of plants and look for knots and nodules on the roots.
Checking for systemic diseases usually involves slicing a stem near the soil at an angle so the core is exposed. Look for discoloration in the stem. One of the diseases can be checked by suspending a piece of sliced stem in a jar of water and watching to see if a white smoke like substance drifts down from the stem.
Do any of the varieties you mention have decent crack resistance? We get very uneven rains most of the time, so cracking is a pretty big issue. We deep mulch with hay to try to keep the moisture as even as possible (we used 20 big round bales at spring planting this year). Supplemental watering is not an option. The soil is already very high in Ca, so I don’t think there is much I can add to the soil to reduce cracking. I’m afraid I have to rely on crack resistance of the cultivars.
Also, can you tell me anything about the size of the varieties you mention? At a farm stand, customers want big tomatoes.
I’m not too overly concerned with late blight tolerance. There are some pretty good fungicides out there with good late blight efficacy, and I can beef up my spray program in that direction, if need be.
Last week I hit the tomato plants with Ranmann which is supposed to be very good on late blight. There are a lot of other fungicide options out there which are very good on late blight, so if I’d have to give up something in order to get good production, flavor, size and crack resistance, I’m willing to give up late blight resistance.
Specs on the varieties are readily available with a search. I took into account your market preference of large fruit with good production and crack tolerance. I did not list a pink tomato, but suggest you look into growing Momotaro and possibly one I released called BBXEPB. Momotaro in particular will fit very well with your customers who like pink tomatoes.
