Good Insects Make A Showing

During the winter while pruning I noticed a healthy looking praying mantis egg case on a cane in the auxerrois block. So when I pruned that cane I stuck one end into a linepost notch near the trellis top not knowing if it was a viable egg ase. Well our granddaughter was out helping us shoot thin in the auxerrois block yesterday and came across the egg case with little mantids emerging. I’m glad she found it as it added a positive experience to a tough day of shoot thinning. Here’s a picture she took. A couple of mantids can be seen. There were many more running away on the trellis wires.


Thanks Gary. I am really interested in what are “good” insects what “bad” insects and grape growers thoughts.

Good questions Sean. Happy to give our thoughts in what we try to achieve every year. It’s important to be in the vineyard daily to see what’s changing and how the plants are progressing. We try to make the vineyard environment conducive for a wildlife balance including the insects. For the most part the insects take care of each other and the birdlife helps in that as well. Some cultural practices like keeping the under-trellis weeds/grass mechanically managed and working to keep the vine canopy open also minimizes any potential insect problems. Also when I know that I will be fungicide spraying I make sure that there is no flowering plants in the vineyard that would attract good pollinators. A quick mowing typically keeps the bees and butterflies out of the vineyard. One point we strongly follow is that it’s key not to be reactive and heavy handed when you see an insect population emerge. It’s best to understand the potential harm by that insect and at what threshold does it create problems for the grapevines. If it’s something specific in the vineyard that we have not seen before, and know nothing about, we take pictures and if stationary(e.g egg cases) we will mark it so that we can come back to it if necessary. There are some things like tomato hornworms and eastern tent caterpillars we manually get rid of on the spot when we see them. There’s only one insect that we selectively take care of each year because they have significant populations and we have suffered immense grape losses and that is the grape berry moth. We watch the wild grapevines flower around our property to understand when the first generation of GBMs will emerge and move to the vinifera grapevines. Previously we put out male GBM lure traps and count the males but now find monitoring the wild grapevines and degree days are solid predictors of GBM egg laying & hatching in the vinifera. The issue we found out the hard way was the unchecked GBM populations will compromise the grapes and create a negative sequence of fruit fly and yellowjacket wasp infestations followed by a complex mix of “rots” on the maturing grapes. Keeping the fruit clean leads to fewer problems because once it starts it’s pretty impossible to get rid of the problem. The only insect that we currently keep an acute lookout for is the spotted lantern fly. It is the one insect that can permanently damage the vines and is very hard to keep in check once it’s in your area. We’re certainly worried about it and it keeps us vigilant in the vineyard and with any new news on population spread in the region and what the latest science tells us on how to deal with them. At this point we know that it’s not an “if” but rather " a when" will we see them. In the past we were concerned with spotted wing drosophila and the marmorated stink bug. Both have turned out to be very minor problems for us. The insects we see each year is a pretty long list so if there are some you are particularly interested in let me know. To restate our approach is to keep the insect populations there and balanced in the vineyard and for us to continually observe whats happening.Cheers !


Bad insects for me are grape berry moth and Japanese beetles. Due to the reasons Gary cited will spray BT for GBM once berries are suseptible. Have been hand picking JB successfully for years, which is good as few things will kill them and those kill everything else as well.

I have a large amount of lady beetles this year. No idea why there are so many more than in the past but it is orders of magnitude more.

Lucky for us our Japanese beetle population went way down and the birds seem to enjoy eating them. Bird poop with shiny beetle parts was the give away sign. When our plants were newly planted we, along with friends, went up and down the rows with soapy water. Now for those that do show up they just help us prune the vines a little bit. We don’t see many beetle larval forms in the soil now. Probably a combination of annual population decline, something in the soil is infecting the larvae, and skunks foraging in the vineyard when the soil softens. We like when things seem to take care of themselves.

Here in glassy-winged sharpshooter country we have no choice but to spray imidacloprid (there actually is a choice to not spray and let the vines die of Pierce’s disease). Even so we still see beneficials here: praying mantis, ladybugs, and lacewings. A tiny wasp (gonatocerus ?) is supposedly native here and parasitizes sharpshooter eggs, but I’ve not seen them.

We have bluebirds and nest boxes for them, and so many owls they don’t need government constructed housing :innocent:

Wow ! I had no idea that you have to spray neo-nicotinoids to protect the plants. What do the biodynamic and organic vineyards do?

Hi Gary

There are no* organic vineyards that survive long in Ventura County. Before we planted in 2013 an ag official told me “viticulture is not viable” in our area, due to PD and GWSS. Of course a good way to get me to do something is for a govt official to say it can’t be done.

In a way he was right: even with imidicloprid (spraying and systemic) we’ve lost vines. I’m not commercial but if I were I wouldn’t recommend trying it here.

*You may know that Andy Walker at UC Davis has bred (conventionally) PD-resistant vines. They are a large % vinifera with enough native american grape to be resistant to PD. The varietals are similar to but not the same as normal vinifera (CS, etc), but according to reports make good wines. I have been replanting these vines to replace those lost to PD. To your question Adam Tolmach / Ojai has planted a vineyard to the PD resistant varietals, and he is an organic kind of guy. Years ago Adam lost his vinifera vineyard in Ojai to PD.

Thank you Kim. When you mentioned Ventura County my first thoughts were to Ojai Vineyards. In looking at the their website and online infection maps it was clear as a bell to the severity of the disease and it’s spread. Looking forward to the day when a viable strategy emerges that does not use neo-nicotinoids. I’m also looking forward to tasting wine made from some of these PD resistant hybrids. Cheers.

Gary, not sure about where you are at but we have a Japanese beetle explosion this year. I have never seen anything like this in the 18 years I have had vines. Still hand picking right now but damage is already at mid July levels. I should have taken pictures as at times there are 20 or more on a single leaf.

I know it is regional here and not local to me. Unsure of cause. They are earlier this year and my hope is most of the increase is from that and population stops increasing soon because if it gets worse from here I will have little choice and have to spray.

Brian - We are in southern New England. Have not seen any Asian or Japanese beetles yet. Usually early July is when we see them emerge. In recent years the population for these beetles has been diminishing.