ABSTRACT Parthenium hysterophorus is an invasive weed that poses significant threats to crop production, biodiversity, human and animal health. Few experiments have been carried out to test the effectiveness of biological control agents such as the beetle Zygogramma bicolorata against this invasive. We released Z. bicolorata beetles as bio-agent to control P. hysterophorus at the Tropical Pesticides Research Institute in Arusha, Tanzania, across two seasons, from February – July 2019 (wet) and August 2019 – January 2020 (dry). Feeding by Z. bicolorata reduced P. hysterophorus leaves, flowers, height as well as biomass, both in the dry and wet season. During the wet season, 100% of all P. hysterophorus leaves were eaten already 28 days after the onset of the experiment, particularly under the highest beetle population treatment (30 individuals). Parthenium hysterophorus flower numbers were greatly reduced under high beetle populations (30 individuals) compared to the control treatment (0 individuals) during both the wet and dry season. Parthenium hysterophorus height was reduced by 87% and 90% during the wet and dry season, respectively when 30 beetles were released. Similarly, biomass was reduced by 90% and 87% during the wet and dry season, respectively. Parthenium hysterophorus responses to beetle treatments did not differ significantly across seasons but the development of both the invasive and its control, Z. bicolorata, was slightly delayed in the dry season. We conclude that Z. bicolorata can be used as bio-agent to manage P. hysterophorus in Tanzania, particularly when released in large numbers.

中文翻译：

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Zygogramma bicolorata 作为生物防治剂对坦桑尼亚阿鲁沙的 Parthenium hysterophorus 的有效性

摘要 Parthenium hysterophorus 是一种侵入性杂草，对作物生产、生物多样性、人类和动物健康构成重大威胁。很少进行实验来测试生物控制剂（例如双色金龟子甲虫）对抗这种入侵的有效性。我们在坦桑尼亚阿鲁沙的热带农药研究所发布了双色甲虫作为生物制剂来控制 P. hysterophorus，跨越两个季节，从 2019 年 2 月至 2019 年 7 月（湿）和 2019 年 8 月至 2020 年 1 月（干）。在旱季和雨季，由双色紫罗兰喂养减少了 P. hysterophorus 的叶子、花朵、高度以及生物量。在雨季，100% 的 P. hysterophorus 叶子在实验开始后 28 天就被吃掉了，特别是在甲虫种群最高的处理（30 只）下。在雨季和旱季，与对照处理（0 只）相比，高甲虫种群（30 只）下的 Parthenium hysterophorus 花数大大减少。Parthenium hysterophorus 高度在雨季和旱季分别降低了 87% 和 90%，释放了 30 只甲虫。同样，在雨季和旱季，生物量分别减少了 90% 和 87%。Parthenium hysterophorus 对甲虫处理的反应在不同季节之间没有显着差异，但侵入性及其对照 Z. bicolorata 的发展在旱季略有延迟。我们得出结论，Z. bicolorata 可用作生物制剂来管理坦桑尼亚的 P. hysterophorus，尤其是在大量释放时。