Japanese Beetles?

This is the time of the year for the annual infestation of Japanese beetles (Popillia japonica). We get a distant early warning of their approach from the vineyard owners in the Mid-Atlantic. For the past 2 years, while our vineyard has become repopulated with vines, the numbers of Japanese beetles appears to have declined.

In 2014, the year after we planted our 6800 vines and the year that we saw only 600 vines survive, we had Japanese beetles everywhere. I blogged about it in a post that I called Beetlejuice because I was using soapy water to catch the critters to lead them to their demise.
How does soapy water work to end the life of a Japanese beetle?¹ Beetles breathe in a way that is fairly sophisticated, using up to 18 tiny openings, called spiracles, that dot the middle and hind part of their bodies. When the pores open, oxygen-rich air can diffuse into tracheal tubes hooked up to the holes. The oxygen then gets shuttled through thousands of interconnected and branching tubes and dumped into cells. The waste product, carbon dioxide, then travels through the tubes and out the holes.
When soapy water is used to capture the Japanese beetles, it is effective in sealing the spiracles thereby preventing them from breathing and ultimately leading to their death. I took particular delight in catching and killing Japanese beetles in this way. My husband said this activity was not sustainable.
Knowing the lifecycle of the Japanese beetle can be helpful in their control. I found an excellent Japanese beetle lifecycle representation in the Sacramento Bee.²

Since we don't use any pesticides or herbicides in the vineyard, we feel that we are allowing the natural predators to be our first line of defense against the invading Japanese beetles.
Natural Control Strategies:³
Parasitic wasps like spring tiphia wasp (Tiphia vernalis) and the beetle’s natural enemies like the Istocheta aldrichi fly are another grub control measure. Starlings are the best known beetle-eaters, eating both the grubs and adult beetles. Other birds known to eat grubs are robins, crows, grackles, catbirds, sparrows, bobwhites, blue jays, eastern kingbirds, woodpeckers and purple martins.
If you see birds pecking at your lawn chances are they may be hunting and eating beetle grubs along with other garden and lawn pests. Japanese beetles prefer to lay their eggs in turf grass that is short, avoiding grass that is more than 2 inches high. Tall grasses harbor natural beetle egg predators like ground spiders and ants. They consume large numbers of beetle eggs in the soil even before they hatch, so keeping your grass on the taller side may be a good defense against the onslaught of Japanese beetles.
We are crossing our fingers and hoping that our natural born predators are consuming copious amounts of Japanese beetle grubs and adults!
References:
1. Jeanna Bryner, Beetle Breathing Highly Complex, Study Finds, Live Science, May 17, 2007.
2. DEBBIE ARRINGTON, Threat of voracious Japanese beetles persists, Sacramento Bee, July 16, 2016.
3. Master Gardeners of Hamilton County, TN, Japanese Beetles – Start Preventing Next Year’s Crop Today, June 17, 2010.

Hedging Duties in the Vineyard

Our friend has been coming to lend us a hand. We are so happy and so are our vines. This week's task is hedging. Hedging should be done from fruit set to véraison. Hedging allows for adequate light exposure of leaves, fruit, and developing buds in dense canopies.
Last year, around this time, we were hedging our vines. It is not too onerous a job when there are very few plants to hedge. But, with this year's 6,000 vines maturing, our friend brought his newly acquired electric hedger and made quick job of hedging our vines.
Do not try this at home!

The results of hedging can be seen here.
Before Hedging:

After Hedging:

Why do we hedge? We have 7 feet between rows, as the vines get taller, they throw shade on the adjacent row so hedging will take care of that problem. Also, we want to be able to spray all of the canopy, so the tops of the canopy being no taller than the top of the trellis will allow for complete spray coverage by our sprayer.
Kudos to our friend, a key talent in the vineyard!
References:
1. Amanda J. Vance, Alison L. Reeve and Patricia A. Skinkis, The Role of Canopy Management in Vine Balance, Oregon State University, June 2013.

Two Stages of Grape Berry Development

Our friend has been helping us with our vineyard work. Recently, we showed him the Chardonnay fruitset 2 weeks after bloom. He was surprised at how large they were and so was I. He said that at this rate, the grape bunch will be huge.

Grapes, however undergo a lag phase between two growth phases. Sneaky berries!
Here is a chart showing all that is going on once berries are set. The chart illustrates the double sigmoidal curve of berry growth and development:¹

Development During First Growth Period2

Development During Second Growth Period

The first period of growth lasts approximately 60 days past bloom The berry is formed and the seed embryos are produced Rapid cell division in the pericarp occurs through the first few weeks, establishing the total number of cells within the berry The berry expands in volume as solutes such as tartaric and malic acid accumulate Tartaric acid appears to accumulate during the initial stages of berry development, and malic acid accumulates just prior to véraison Hydroxycinnamic acid also accumulates during the initial period of growth Tannins including the monomeric catechins also accumulate during the first period of growth Minerals, amino acids, micronutrients, and aroma compounds (such as methoxypyrazines have all been observed during the first period of berry growth

The first growth period is followed by a lag phase during which little or no growth occurs. The second growth phase coincides with the onset of ripening (veraison) Cells in the pericarp undergo expansion The berry expands in size due to the influx of water, carbon and mineral nutrients Softening and coloring of the berry occurs during ripening Synthesis and accumulation of anthocyanins occur during ripening There is an increase in abscisic acid (ABA), sugar levels and color development The big change during the second growth period is the accumulation of glucose and fructose as the grape shifts into ripening mode Important aroma and flavor compounds are produced late in fruit ripening The berry approximately doubles in size between the start of ripening and harvest

It is important to understand the development of the grape berry because knowing when flowering occurs, the lag phase can be predicted. In our case, if flowering occurred during late June, our lag phase will be toward the end of August. Our nets should be up by that time to prevent the birds from eating the fruits of our labor!

References:
1. Moschou, Panagiotis & Aziz, Aziz & Roubelakis-Angelakis, Kalliopi, Chapter 7, Polyamines and grape berry development, The Biochemistry of the Grape Berry, (2012), 137-159.
2. James Kennedy, Understanding Grape Berry Development, Practical Winery and Vineyard Journal, July/August 2002.

Events Post Capfall

The European grape varieties that we have planted in our vineyard have perfect flowers, which means that they contain both the male and female reproductive organs and are therefore self-pollinating. They do not require bees to be pollinated.
Events that occur immediately post capfall include the following:¹

Grape Flower Parts

Pollination/Fertilization

Immediately after capfall, the anthers split open and release their pollen grains The pollen grains adhere to substances secreted on the stigma Pollination is complete once the pollen has reached the stigma The pollen grains germinate and form pollen tubes The male gametes (sperm) travel through the pollen tube to the ovary Fertilization occurs when sperm reaches and impregnates the eggs within the embryo sacs Under normal field conditions, fertilization typically occurs two to three days after pollination

References:
1. NiCk K. DokoozLian, Grape Berry Growth and Development.