Depto de Entomologia, Univ Federal de Viçosa, Viçosa, MG, Brazil.
Neotrop Entomol. 2021 Apr;50(2):298-302. doi: 10.1007/s13744-021-00849-3. Epub 2021 Mar 8.
The diamondback moth (DBM), Plutella xylostella (L.) (Lep.: Plutellidae), is an important pest of broccoli (Brassica oleracea L. var. italica Plenck). Few studies have focused on the real DBM impact on broccoli yield. We performed greenhouse studies to assess the effect of DBM densities and infestation timing (at pre-heading, heading, or during the entire cycle) on broccoli head weight. Polynomial trend analysis revealed a downward linear response of head weight to DBM densities, indicating that broccoli is susceptible to DBM attack. As for the infestation timing, infestations during the pre-heading stage significantly impacted head weight, whereas the same did not occur for infestations during the heading stage. DBM density did not affect plant height or total leaves but was upward-related to plant defoliation, and head weight correlated negatively with plant defoliation. These findings indicate that pre-heading is the determining stage for head weight loss of plants under DBM attack. In order to prevent quantitative losses, efforts for DBM management should be focused on this particular stage.
小菜蛾（DBM），也称粉纹夜蛾，属鳞翅目菜蛾科，是西兰花（ Brassica oleracea L. var. italica Plenck）的重要害虫。目前很少有研究关注小菜蛾对西兰花产量的实际影响。我们在温室中进行了研究，以评估小菜蛾密度和侵染时间（在抽薹前、抽薹期或整个周期）对西兰花头重的影响。多项式趋势分析显示，头重与小菜蛾密度呈向下线性响应，表明西兰花易受小菜蛾的攻击。至于侵染时间，抽薹前阶段的侵染显著影响头重，而抽薹期的侵染则没有影响。小菜蛾密度不会影响株高或总叶片数，但与植株的叶片脱落率呈正相关，而头重与植株的叶片脱落率呈负相关。这些发现表明，抽薹前是 DBM 攻击下植株头重损失的决定性阶段。为了防止数量损失，小菜蛾管理应侧重于这一特定阶段。
