The French plum trees at Massa Estate Organic Vineyards have an important job to do.

It is French plum harvesting season at Massa Estate Organic Vineyards. High in the Cachagua region of Carmel Valley, the fruit trees flank the rows of grapes that are now plump and ripe and ready for harvest. Butterflies, bees and birds abound, creating a cacophony of buzzing and trills. In the early afternoon, the sunshine reveals small burgundy plums that seem to hide among the branches.

But the French plum trees at Massa Estate (formerly Heller Estate) are not only a pretty sight – they play an important role in the life of the vineyard. The trees host trichogramma, a wasp that lays its eggs into the larvae of destructive insects – especially the grape moth. Before the moth eggs hatch, the wasps are there to kill them. The wasps then go home to their nests in the French plum trees. The use of trichogramma as pest control has roots in the Alsace region of France; the Heller family brought the technique to the Massa Estate property in the 1980s.

“We just leave the trees alone, and the wasps do their job,” owner Laurie Massa says. “They are very happy here.”

The vineyards were certified organic in the 1980s, and the winery earned the distinction in 2012. Massa is running it all with an eye on maintaining the ecological balance, and treats the wasps as instrumental in ensuring fruit quality for their grapes, as well as lemons, avocados and, of course, the French plum. “When you’re a small organic business, your toolbox is small, so you need help from Mother Nature,” Massa says.

MASSA ESTATE ORGANIC WINERY is at 69 W. Carmel Valley Road, Carmel Valley. 659-6220, hellerestate.com