New Zealand Journal of
Agricultural Research abstracts
Occurrence and impact of
pasture mealybug (Balanococcus
poae) and root aphid (Aploneura
lentisci) on ryegrass (Lolium
spp.) with and without infection
by Neotyphodium
fungal endophytes
C. G. L. Pennell1
A. J. Popay2*
O. J-P. Ball3†
D. E. Hume3
D. B. Baird1
1AgResearch
Lincoln
Private Bag 60
Lincoln, New Zealand
2AgResearch
Ruakura
Private Bag
3123
Hamilton, New Zealand
3AgResearch
Grasslands
Private Bag
11 008
Palmerston North, New Zealand
†Present address:
Northland Polytechnic, Private Bag 9019, Whangarei, New Zealand.
Abstract Pasture
mealybug (Balanococcus poae)
was found infesting
two field trials evaluating the performance of selected strains of the
endophyte Neotyphodium lolii
in ryegrass (Lolium
spp.) in Canterbury, New Zealand. Deterioration of endophyte-free plots
relative to endophyte-infected plots had been observed. In Trial A,
pasture mealybug were sampled in plots of the perennial ryegrass
cultivar ‘Grasslands Nui’, without endophyte (nil), or infected with
the wild-type endophyte, or the selected strains, AR1 and AR37. In
Trial B, mealybug numbers on six ryegrass cultivars infected with AR1
or wild-type were compared with those on the same cultivars without
endophyte. In sampling these trials, the presence of a root aphid, Aploneura
lentisci, was also noted.
Populations of mealybug in both trials were similar on all
endophyte-infected treatments and significantly lower than populations
on nil treatments. Neither AR1 nor wild-type appeared to reduce root
aphid numbers, while AR37 may have had some effect. The amount
of dead grass was significantly greater in nil than in
endophyte-infected plots in Trial A, and yield of ryegrass was
correlated with numbers of mealybug and root aphid present. Pasture
productivity in nil treatments had recovered by spring, in the year of
the outbreak. The presence of endophyte, strain of endophyte and
cultivar were all significant factors affecting both total dry matter
and green yield in Trial B. Pasture mealybug accounted for 55%
of the variation in a decline in growth rate that occurred in this
trial over the summer-autumn periods between 2000 and 2001,
particularly in the nil treatments. Two years after the outbreak there
was 25% less ryegrass and persistently lower pasture yields in nil
plots. We conclude that pasture mealybug are capable of inflicting
severe damage to endophyte-free ryegrass in Canterbury, particularly
during dry summer-autumn periods.
Keywords endophyte;
plant resistance; Neotyphodium
lolii; perennial ryegrass; Balanococcus
poae; Aploneura
lentisci;
drought; pasture production
A04081; Received 26 July 2004;
accepted 2 May 2005; Online publication date 4 August 2005
New Zealand Journal of
Agricultural Research, 2005, Vol. 48:
329–337
0028–8233/05/4803–0329 © The Royal Society of New
Zealand 2005
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