A nematode is an unsegmented, microcsopic worm. Many have stylets which pierce plant parts in order to feed. Some are “ectoparasites” living outside of the plant. Others are “endoparasites” living inside the plant.
“Anguina pacificae” is an endoparasitic gall nema affecting "poa annua" found from San Francisco to Monterey, usually within 10 miles of the coast. Recently it has been identified locally outside the area. The nema lives in a “bulb” at the crown of the plant. Anguina spends it’s entire life inside the plant and only leave for hours at a time to find a new host. (This fact alone makes it very difficult to eradicate)
The gall as well as their feeding disrupt plant processes. Infected plants yellow, decline, die and leave bare spots in greens called “pitting”. The damage is most severe during colder months when recovery, new growth or germination is at a minimum.
Because of the disruption caused by the gall, plants do not respond well to soil applied fertilizer and instead must be foliar fed.
The chemical control is Nemacur. This nematicide is is one of the most toxic chemicals used in golf course management (toxicity doesn't mean it can't be used safely). It is relatively effective for a period of time. Users report eventual reduced effectiveness and shortened intervals of application. This is a temporary tool, as it will be taken off the market in a few years. Besides toxicity, another downside of using Nemacur is that if kills beneficial organisms in the soil.
Bentgrass is not affected by anguina.