Charlet Laurence D, Knodel Janet J
Northern Crop Science Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Fargo, ND 58105-5677, USA.
J Econ Entomol. 2003 Jun;96(3):706-13. doi: 10.1603/0022-0493-96.3.706.
The sunflower beetle, Zygogramma exclamationis (F.), is the major defoliating pest of sunflower (Helianthus annuus L.). Planting date was evaluated as a potential management tool in a variety of production regions throughout North Dakota from 1997 to 1999, for its impact on sunflower beetle population density of both adults and larvae, defoliation caused by both feeding stages, seed yield, oil content, and larval parasitism in cultivated sunflower. Results from this 3-yr study revealed that sunflower beetle adult and larval populations decreased as planting date was delayed. Delayed planting also reduced defoliation from adult and larval feeding, which is consistent with the lower numbers of the beetles present in the later seeded plots. Even a planting delay of only 1 wk was sufficient to significantly reduce feeding damage to the sunflower plant. Yield reduction caused by leaf destruction of the sunflower beetle adults and larvae was clearly evident in the first year of the study. The other component of sunflower yield, oil content, did not appear to be influenced by beetle feeding. The tachinid parasitoid, Myiopharus macellus (Rheinhard), appeared to be a significant mortality factor of sunflower beetle larvae at most locations regardless of the dates of planting, and was able to attack and parasitize the beetle at various larval densities. The results of this investigation showed the potential of delayed planting date as an effective integrated pest management tactic to reduce sunflower beetle adults, larvae, and their resulting defoliation. In addition, altering planting dates was compatible with biological control of the beetle, because delaying the planting date did not reduce the effectiveness of the parasitic fly, M. macellus, which attacks the sunflower beetle larvae.
向日葵叶甲（Zygogramma exclamationis (F.)）是向日葵（Helianthus annuus L.）的主要食叶害虫。1997年至1999年期间，在北达科他州的多个生产区域对播种日期作为一种潜在管理手段进行了评估，以研究其对栽培向日葵中向日葵叶甲成虫和幼虫种群密度、两个取食阶段造成的落叶、种子产量、含油量以及幼虫寄生情况的影响。这项为期3年的研究结果表明，随着播种日期推迟，向日葵叶甲成虫和幼虫数量减少。推迟播种还减少了成虫和幼虫取食造成的落叶，这与晚播地块中甲虫数量较少相一致。即使仅推迟1周播种也足以显著减少对向日葵植株的取食损害。在研究的第一年，向日葵叶甲成虫和幼虫造成的叶片破坏导致的产量下降明显可见。向日葵产量的另一个组成部分，含油量，似乎不受甲虫取食的影响。无论播种日期如何，寄蝇类寄生蜂Myiopharus macellus (Rheinhard)在大多数地点似乎都是向日葵叶甲幼虫的一个重要致死因素，并且能够在不同幼虫密度下攻击并寄生该甲虫。这项调查结果表明，推迟播种日期作为一种有效的综合害虫管理策略具有减少向日葵叶甲成虫、幼虫及其造成的落叶的潜力。此外，改变播种日期与对该甲虫的生物防治是相容的，因为推迟播种日期并未降低攻击向日葵叶甲幼虫的寄生蝇M. macellus的有效性。
