pdf, 57.71Mb - Entomological Society of Canada
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46 C. H. Craig and C. C. Loan<br />
Releases and Recoveries<br />
Recommendations<br />
Table 6<br />
A programme to supplement the natural parasitism in Lygus populations in western<br />
<strong>Canada</strong> was started in 1977 with the first collection and shipment to Ottawa <strong>of</strong> parasitoids<br />
<strong>of</strong> European Lyglls, and in 1978 with the first liberations <strong>of</strong> these in western<br />
<strong>Canada</strong>. Table 6 shows the progression <strong>of</strong> liberations in the period 1978-81 inclusive.<br />
Liberations <strong>of</strong> Peristenus spp. in alfalfa against Lygus spp. in western<br />
<strong>Canada</strong>.<br />
Date <strong>of</strong> liberation Location <strong>of</strong> liberation site<br />
7 June 1978<br />
9 June 1978<br />
13 June 1978<br />
21 June 1978<br />
14 June 1979<br />
21 June 1979<br />
29 June 1979<br />
29 May 1980<br />
3 June 1980<br />
10 June 1980<br />
10 June 1980<br />
6 June 1981<br />
6 June 1981<br />
!<br />
}<br />
Moose Jaw, Saskatchewan; 50 o N;<br />
shortgrass prairie; dry<br />
Saskatoon, Saskatchewan; 52°N;<br />
mixed prairie; dry<br />
Tilley, Alberta; 50 0 30'N;<br />
shortgrass prairie;<br />
irrigated<br />
Shellbrook, Saskatchewan; 53°N;<br />
parkland-mixed forest; dry<br />
Ardath, Saskatchewan; 51°30'N;<br />
mixed prairie; dry<br />
Shellbrook, Saskatchewan<br />
(supplement to 1979 release)<br />
Saskatoon, Saskatchewan<br />
mixed prairie; irrigated<br />
Saskatoon, Saskatchewan<br />
(supplement to 1978 release)<br />
Yellow Creek, Saskatchewan;<br />
53°N parkland; dry<br />
Saskatoon, Saskatchewan<br />
(supplement to 1980 release)<br />
Species<br />
P. digoneLltis<br />
P. digoneLltis<br />
P. digoneutis<br />
P. stygicus<br />
P. digoneLltis<br />
P. srygicus<br />
P. digoneLltis<br />
P. digoneutis<br />
P. digoneutis<br />
P. digoneutis<br />
P. digoneutis<br />
P. digoneutis<br />
Number<br />
The imported parasitoids were released into Lygus populations breeding in alfalfa<br />
fields used for seed production. The lifespan <strong>of</strong> the sites for sampling purposes is about<br />
5 years, and during that time they are subject to normal alfalfa seed cropping practices.<br />
Intensive sampling for presence <strong>of</strong> adult Peristenus and mass collection <strong>of</strong> host<br />
nymphs for parasitoid rearing was started the year follOwing the initial liberations and<br />
continued for at least three ensuing years. In 1979-80, a total <strong>of</strong> 274 parasitoid adults,<br />
either captured at the liberation sites or reared from Lygus hosts collected from alfalfa<br />
at the liberation sites, were the native species, Peristenus pallipes. No introduced<br />
parasitoids have been recovered.<br />
The introduction and liberation <strong>of</strong> Peristenus parasitoids will terminate in the spring <strong>of</strong><br />
1981. During the next few years attempts will be made to recover the introduced<br />
parasitoids and to evaluate the programme.<br />
197<br />
177<br />
541<br />
41<br />
159<br />
23<br />
167<br />
261<br />
80<br />
138<br />
125<br />
115
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