Gaire Susmita, Albrecht Ute, Batuman Ozgur, Zekri Mongi, Alferez Fernando
Southwest Florida Research and Education Center, Institute of Food and Agricultural Sciences (UF-IFAS), University of Florida, Immokalee, FL 34142, USA.
Hendry County Extension, Institute of Food and Agricultural Sciences (UF-IFAS), University of Florida, 1085 Pratt Blvd, LaBelle, FL 27695, USA.
Plants (Basel). 2024 Aug 17;13(16):2284. doi: 10.3390/plants13162284.
The use of individual protective covers (IPCs) to protect newly planted citrus trees from Huanglongbing (HLB) infection is being widely adopted in Florida, an HLB-endemic citrus-producing area. It is known that IPCs positively influence most horticultural traits, increasing tree growth, flush expansion, and leaf size, enabling trees to sustain balanced carbohydrate metabolism by preventing (Las) infection, and inducing higher leaf chlorophyll levels. This may result in more productive trees. However, as the tree grows, IPCs eventually are removed, typically between 2 and 3 years after their initial installation. Once IPCs are removed, trees become exposed to the Asian citrus psyllid (ACPs) and ultimately become infected. In this work, we covered Valencia sweet orange trees with IPCs for 30 months, until the trees entered fruit-bearing age. We investigated how the IPC protection of newly planted trees for 30 months influenced the fruit quality and yield of "Valencia" trees for three consecutive seasons after IPC removal compared to non-covered trees. The use of IPCs kick-started the newly planted citrus trees, resulting in higher yields and fruits with better internal and external quality. After 30 months of IPC protection, tree canopies were larger and denser, supporting more fruit per tree than non-protected trees for three consecutive seasons, even though by the end of the first season after IPC removal, the trees were HLB-positive. Tree height, scion diameter, canopy volume, and leaf area were significantly improved compared to non-covered trees. Additionally, fruit quality was significantly improved in the three seasons following IPC removal compared to non-covered trees. However, a decline in quality was measurable in fruit from IPC trees after the second harvesting season, with trees affected by HLB. Based on the results from this study, we conclude that the benefits from IPC protection may last for at least three consecutive seasons once trees enter the productive age, despite Las infection within 12 months after IPC removal.
在黄龙病（HLB）流行的柑橘产区佛罗里达州，使用个体防护套（IPCs）来保护新种植的柑橘树免受HLB感染的做法正在广泛采用。已知IPCs对大多数园艺性状有积极影响，可促进树木生长、梢叶扩展和叶片增大，通过防止感染黄龙病菌（Las）使树木维持碳水化合物代谢平衡，并诱导叶片叶绿素水平升高。这可能会使树木产量更高。然而，随着树木生长，IPCs最终会被移除，通常在初次安装后的2至3年之间。一旦移除IPCs，树木就会暴露于亚洲柑橘木虱（ACPs）之下，最终感染黄龙病。在这项研究中，我们用IPCs覆盖伏令夏橙树30个月，直至树木进入结果期。我们研究了新种植树木30个月的IPCs保护对移除IPCs后连续三个季节的“伏令夏”树果实品质和产量的影响，并与未覆盖防护套的树木进行了比较。IPCs的使用促进了新种植柑橘树的生长，从而提高了产量，果实的内外品质也更好。经过30个月的IPCs保护后，树冠更大更密，连续三个季节每棵树的果实数量都比未受保护的树木多，尽管在移除IPCs后的第一个季节末，这些树已感染HLB呈阳性。与未覆盖防护套的树木相比，树高、接穗直径、树冠体积和叶面积都有显著改善。此外，与未覆盖防护套的树木相比，移除IPCs后的三个季节里果实品质也有显著提高。然而，在第二个收获季节后，受HLB影响的IPCs树所结果实的品质出现了可测量的下降。基于这项研究的结果，我们得出结论，尽管在移除IPCs后的12个月内感染了Las，但一旦树木进入结果期，IPCs保护带来的益处可能至少持续三个连续季节。
