Case Study - Lahinch Golf Club
Lahinch Golf Club experienced heavy infestations of Chafer Grubs (confirmed as Phyllopertha horticola by the STRI), and several fairways and large areas were dug up by crows and starlings. These areas of grass had been re-turfed two years ago; most areas which were re-laid with this batch of turf had chafer problems.
On the Old Course a number of fairways were affected along a number of tee boxes on the Castle Course. John Rouine, Superintendent at Lahinch explained, "They have never been this big a problem before. You sometimes used to get small patches but never this scale".
Lahinch tried a number of cultural methods to reduce the visible damage, including bird control and weekly visits from a hawk, and also spraying garlic onto the grass to deter bird feeding. John Rouine explained, "The hawk worked very well but we did not have great results with the garlic barrier." Unfortunately the hawk could not be on site permanently.
Preventing the birds from feeding would not have solved the problem as, by not reducing the grub numbers, they would likely just return the following year in even higher numbers.
The ground staff applied Nemasys G from one of their boom sprayers on a rainy day in September 2007. Because of the rain few golfers were on the course and, because there is no re-entry interval, those who had braved the weather did not have their round disturbed. The beneficial nematodes gave a very rapid knock down effect.
The product stopped Chafer Grubs feeding within three days of application, enabling the roots to start recovering. Grubs die within 10-14 days.
Secondary damage also stops, as predators are no longer feeding off the grubs. Two weeks after application re-establishment work on the turf, such
as re-seeding, could begin.
Four weeks after application, the level of grubs were dramatically lower and the grass was already showing signs of recovery, and in July 2008 there was no evidence of secondary damage on the previously damaged fairways. Thanks to the efforts of the ground staff and course superintendent, John Rouine, Lahinch Golf Club now has an integrated control programme to ensure this problem does not arise again. Nemasys G will be blanket sprayed over the whole course in early October to keep on top of this infestation, and work on eliminating this pest for good.
Chafer Grub Life Cycle
Adult Chafers are medium-sized reddish brown beetles about 13-15mm long. It is the grub stage however that is most likely to be found in turf.
Damage is usually most evident in August and September.
Early symptoms include gradual thinning, yellowing, and weakening of the grass stand followed by the appearance of scattered, irregular dead patches.As damage continues, the dead patches may increase in size, and apparently healthy turf areas may exhibit sudden wilting. The turf may feel spongy as you walk over the infested area.
Adult Chafers emerge from the pupal cells in mid-June and continue mating until late July.The adults emerge at dusk and fly to nearby trees and shrubs where copulation begins.This copulation occurs in mass until dawn when adults return to the soil. Cool or rainy nights greatly reduce flight and mating
activities, but eventually females dig into the soil and lay eggs.
Each female lays 15-20 eggs in 2-5 days.They are usually laid in compacted soil, up to 150mm deep.
The eggs swell to approximately 2.0 x 2.7mm as they absorb moisture and hatch in about two weeks.The first instar (stage) are approximately 4mm long and may remain in the soil if surface moisture levels are low. however eventually the young larvae move to the surface and feed on plant roots.
If food is sufficient, the first instar matures in three weeks and the second instars take a further four weeks to mature.The third instars which can grow to 17mm when fully grown feed for a period in the autumn before moving down into the soil for the winter.
Pupation then occurs in mid-May 50 to 150mm into the soil.
Order Nemasys Chafer Grub Killer online or by contacting your local Everris distributor.