Studies on May beetles injurious to the turfgrass XV
Life history, ecology and prevalence habit of turfgrass injurious chafer, Anomala osakana SAWADA
1982 Volume 11 Issue 1 Pages 77-85
Details
1982 Volume 11 Issue 1 Pages 77-85
The author investigated the life history, ecology and seasonal habit of Anomala osakana Sawada, a species of the most turfgrassinjurious insects to obtain useful information on controlling this chafer. The results are summarized as follows:
1. Adults emerged on the ground from the early part of June through the middle of August. The peak of adult emergence was in the middle of June. The adults, having nocturnal habit, emerged on the ground soon after the sunset. After flying in swarms, they copulated. Most of the adults were males and the flying in swarms was between 7 and 9 o'clock p. m.
2. Adults of both sexes emerged on the ground after about a week of the latent period following the adult emergence. Males emerged all days in continuation of 3 to 10 days. Most females emerged only once individually.
3. The life span and oviposition of the adults are supposed to be not affected by feeding on turfgrass. The life span of males is 16.3 days and that of females 17.1 days. The number of eggs laid is 45.2.
4. The adults ovipostted in the latter part of June. The length of egg stage is 16.0 days at room temperature with the average percentage of egg hatch of 97.7 per cent.
5. Eggs were oval, 1.76 mm in longer diameter and 1.29 mm In shorter one. Directly before the hatch the eggs reached 3.48 times the initial weight.
6. Larvae directly after the hatch emerged in the early part of July and grew while injuring turfgrass roots. Second-stage larvae emerged in the middle of July and third-stage grubs emerged in the middle of August and they wintered.
7. The frequency distribution curve of width of head capsuule of larvae has three distinct peaks. Therefore, the larvae seems to molt three times. The lengths of the first and second stages are both about 20 to 25 days.
8. The ground abundant in the larvae has a high moisture content.
9. Pupae emerged in the latter part of May. The length of pupal stage was 12.1 days at 25°C. The average percentage of adult emergence was 95%.
10. Damage of turf grass grounds by the larvae increased in and after the middle of August. Further, as the secondary damage, it was observed that crows pick over the ground to catch the larvae.
11. To control this chafer, it would be advisable to spray a pesticide capable of retaining residual effects over a long period on the ground in the middle or latter part of June, when the adults will emerge, as in the contrl of Anomala schönfeldti Ohaus.
