scholarly journals Comparisons of traps and lures for monitoring grass grub Costelytra zealandica

2008 ◽  
Vol 61 ◽  
pp. 215-221
Author(s):  
C.R. Unelius ◽  
R.J. Townsend ◽  
D.C. Mundy ◽  
L.M. Manning ◽  
T.A. Jackson ◽  
...  

Phenol the attractant pheromone of adult males of the native New Zealand grass grub Costelytra zealandica (White) is produced in the beetles as the result of bacterial degradation of tyrosine A lure consisting of a resin impregnated with phenol has been widely used to monitor male beetle flight activity The present formulation is highly attractive for the first week in the field but then loses activity rapidly A number of phenolcontaining formulations were tested to improve the lure A new formulation gave lower catches that were more stable with time producing data more suitable for population density estimation Phenylacetaldehyde a bacterial metabolite of phenylalanine was tested as a possible synergist to phenol Field results showed that this floral compound exhibited no behaviourallyactive properties to grass grubs when tested together with phenol Catches with water traps were compared with those in sticky delta and flat delta traps in two vineyards and in pasture Water traps caught four times more beetles

2004 ◽  
Vol 57 ◽  
pp. 310-313 ◽  
Author(s):  
R.J. Townsend ◽  
T.A. Jackson ◽  
C.M. Ferguson ◽  
J.R. Proffitt ◽  
M.W.A. Slay ◽  
...  

The bacterium Serratia entomophila is a naturally occurring pathogen causing amber disease of the New Zealand grass grub (Costelytra zealandica) A novel granular formulation of S entomophila Bioshieldtrade; was applied to 18 pasture sites in a largescale programme to demonstrate efficacy against grass grub No significant difficulties were encountered in application of the granules through conventional machinery There were high populations of the applied bacteria in soil within the first week of application and within 6 weeks of application there was an average of 3 x 104 viable S entomophila of the applied strain per gram of soil This resulted in a significant (Plt;005) 20 increase in the incidence of amber disease in the treated grass grub populations compared to untreated populations Successful establishment of the bacteria in the soil and target population following Bioshieldtrade; granule application was demonstrated on a wide range of sites under various farming conditions


2009 ◽  
Vol 62 ◽  
pp. 395-395
Author(s):  
M. Brownbridge ◽  
R.J. Townsend ◽  
T.L. Nelson ◽  
B. Gicquel ◽  
M. Gengos

The Australian pasture pest Adoryphorus couloni (redheaded cockchafer RHCC) continues to slowly spread from the Port Hills and Banks Peninsula through Christchurch towards productive agricultural land on the Canterbury Plains There are currently no products chemical or biological registered in New Zealand to control this pest In Christchurch several parks used extensively for human recreation were badly damaged by RHCC grubs in the autumn/early winter of 2008 and had to be treated with chemical insecticides (diazinon) Laboratory trials were thus carried out to assess the susceptibility of New Zealand populations of RHCC to a microbial biocontrol agent Metarhizium anisopliae DATF001 (ChaferGuard) registered in Australia Fungal activity was directly influenced by temperature and mode of application Infection and mortality occurred faster at 20C than 15C High mortality levels (90100 after 7 weeks) were obtained when larvae were treated by topical application (105 conidia/grub) or exposure to the dry ChaferGuard formulation in soil; >80 of the cadavers in these treatments were mycosed Direct incorporation of conidia into soil was the least effective treatment Grass grub (Costelytra zealandica) was unaffected by the fungus This trial confirmed the efficacy of DATF001 and its potential for use against New Zealand populations of RHCC


2003 ◽  
Vol 56 ◽  
pp. 123-128 ◽  
Author(s):  
A.J. Popay ◽  
R.J. Townsend ◽  
L.R. Fletcher

Grass grub (Costelytra zealandica) population density mean larval weight and visible damage were lower in meadow fescue (Festuca pratensis) infected with the endophyte Neotyphodium uncinatum (E) than in uninfected meadow fescue (E) in an unreplicated field trial In two bioassays third instar grass grubs ate all meadow fescue E roots but significantly less of the E roots Larvae fed E roots lost weight at the same rate as unfed control larvae Larvae given a choice between maize and either E or E meadow fescue in a pot trial consumed 33 more of the maize in the E treatment than in the E treatment Weight gain of larvae in E treatments was significantly less than in E in both the choice and nochoice pot trials but survival was the same It was concluded that meadow fescue infected with N uncinatum deters grass grub larval feeding but has no major toxic effects


Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 825
Author(s):  
Maydianne C. B. Andrade ◽  
Aiswarya Baskaran ◽  
Maria Daniela Biaggio ◽  
Maria Modanu

Female choice may be linked to population density if the expected encounter rates with potential mates affects choosiness (the energy and risk engaged to express mate preferences). Choosiness should covary with male availability, which could be assessed using the social cues available during development. We tested whether the exposure of juvenile females to cues of male density affected the mechanisms of choosiness of adult Latrodectus hasselti spiders in two experiments simulating natural contexts. The juvenile females were exposed to (1) volatile chemicals from two densities of adult males (airborne cues), and (2) tactile, vibrational and chemical cues from adult males or other females (cohabitation cues). As adults, the females mated readily, regardless of the treatment, but there was strong evidence for post-copulatory mechanisms of choosiness in females exposed to cues of high male availability. These included abbreviated matings (in both experiments), cannibalism of the males before the mating was complete (cohabitation), and, remarkably, a reduction in the successful placement of internal sperm plugs (cohabitation). These shifts decrease the likelihood that the first mate would monopolize paternity if the female chose to mate again. We conclude that female choosiness may impose a strong selection on males despite the high mating rates, and these effects can hinge on the cues of male availability detected by juveniles.


1995 ◽  
Vol 18 (1) ◽  
pp. 71
Author(s):  
J.L. Gardner ◽  
M. Serena

The Water Rat Hydromys chrysogaster is Australia's largest amphibious rodent, occupying freshwater rivers, lakes, and coastal and estuarine habitats throughout the continent (Watts and Aslin 1981). Little is known of the species' social organisation or use of space in the wild although Harris (1978) suggested that adults might be intrasexually aggressive. The home ranges of all sex and age classes overlap to some extent but home ranges of adults of the same sex appear to overlap less (Harris 1978). Adult males occupy the largest home ranges which overlap those of one or more females. In captivity individuals kept in groups form hierarchies in which only the dominant females usually breed successfully (Olsen 1982). Fighting occurs primarily among males, with the highest incidence of injuries observed at the beginning of the main September-March breeding season (Olsen 1980, 1982). The results of trapping studies indicate that population density may vary considerably, with the greatest numbers of animals typically occupying man-modified habitats such as irrigation channels or fish farms (McNally 1960, Watts and Aslin 1981, Smales 1984). Aggressive behaviour appears to be related to pelage colour (phenotype) and population density; the higher the density the greater the number of injured individuals (Olsen 1980).


1958 ◽  
Vol 9 (1) ◽  
pp. 138 ◽  
Author(s):  
SK Stephenson

Quantitative aspects of follicle initiation and development have been studied in a series of N-type and New Zealand Romney foetuses. Density of the follicle population and ratios of secondary to primary follicles were examined on 13 positions of the body which covered the main wool-bearing areas, the face and head, and the limbs. Primary follicle development is initiated first on the head and limbs and throughout subsequent development these regions are most advanced. Primary follicle density reaches a maximum between 75 and 90 days of foetal age, after which it decreases as a result of skin growth. Secondary follicle initiation is more rapid on the wool-bearing areas of the body, and higher ratios of secondary to primary follicles are recorded from these regions. No real differences have been found between N-type and New Zealand Romney foetuses in population density of the different follicle types at any age or in the number of secondary follicles developed per primary follicle. The growth of larger primary fibres and follicles in N-type foetuses is not accompanied by, and does not result from, a lower density of primary follicles. There does not appear to be any marked relation between the decreasing density of primary follicles after 90 days of foetal age and the initiation of secondary follicle anlagen. This fact, and the absence of any differences in the number of secondary anlagen formed per primary follicle in N-types, suggest that crowding in N-types is not a limiting factor in the formation of secondary follicle anlagen.


1952 ◽  
Vol 3 (1) ◽  
pp. 32 ◽  
Author(s):  
AMR Burnet

Experimental trapping of eels, using carrion-baited traps, was carried out on a number of rivers of various types throughout New Zealand. Where possible, a mathematical analysis has been applied to the trapping results and an estimate of the efficiency obtained. Total trappable population densities of between 30 and 1,368 lb./ac. Were found. An attempt has been made to correlate type of river with the population density. The amount of cover present is apparently the limiting factor. The baited trap takes very few eels of less than 24 in. long and is thus not a very efficient means of keeping a stream free from eels. The feeding habits of the eel are generalized and readily adaptable to most faunas. In most rivers trout occurred only infrequently in the stomach contents.


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