25 May 2021
HLB

CRISPR/Cas technology could enable early diagnosis of devastating citrus disease

Scientists from Penn State and the U.S. Department of Agriculture have developed a diagnostic test that enables early detection of Huanglongbing (HLB) by detecting the presence of the bacterium that causes the disease, i.e. Candidatus Liberibacter asiaticus (CLas). Early detection of CLas is vital in controlling the spread of HLB because trees that have been infected by CLas can serve as a disease reservoir for years before symptoms are visible.

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28 Apr 2021
Trapping 2021

Trapping for Asian Citrus Psyllid in Southern Africa: Feb / Mar 2021

The article describes how the presence of the Asian Citrus Psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), in parts of Africa, most recently trapped in southwestern Tanzania and Kenya, is increasing the risk to citriculture in Southern Africa. ACP is an effective vector of Huanglongbing (HLB), which is a destructive citrus greening disease and is associated with the gram negative α-Proteobacteria Candidatus Liberibacter asiaticus (Las).

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05 Dec 2020
Orange Fields

Understanding disease-induced microbial shifts may reveal new crop management strategies.

Researchers at the University of California studied the role of the tree’s microbiome in the progression of citrus greening disease. They used amplicon technology to study the microbiome during the progression of HLB, and found that harmful microbes increased, while beneficial microbes decreased during the disease progression.

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05 Dec 2020
Cover Crops

Cover crops for citrus

Cover crops are specific crops not intended for sale but for soil improvement and sustainability. They are increasingly common in the agricultural fields of the Midwest and other grain-producing regions because of the wide range of benefits not just for the soil, but also the cash crop. In those systems, cover crops improve water and nutrient retention, promote microbial activity, reduce weed growth and insect pests, and improve plant growth. Similar impacts have been found in tree crops like apples and peaches, where cover crops are planted in row middles.

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29 Jul 2020
Citrus Green

Solution found to Citrus Greening Disease

University of California finds substance capable of controlling devastating citrus disease

Scientists at the University of California, Riverside (UCR) have found the first substance capable of controlling Citrus Greening Disease, which has devastated citrus farms in Florida and also threatens California.

The University of Florida has also been working towards a solution, as reported in March 2020.

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29 Jun 2020
Citrus Rehabilitation from HLB

Rehabilitation of HLB infected citrus trees using severe pruning and nutritional sprays.

Citrus trees infected with Huanglongbing (HLB) bacteria become weak and develop dieback, resulting in lost production. These trees eventually decline to a production level that is not economical to maintain in a citrus operation. Sixteen-year-old ‘Valencia’ (Citrus sinensis Macf.) orange trees on Swingle citrumelo rootstock [C. paradisi × Poncirus trifoliata (L.) Raf.], 100% infected with HLB, in decline and losing production, were severely pruned (buckhorned) to stimulate regrowth and the new flush treated with foliar nutritional sprays. Nutritional sprays included the “Boyd cocktail” and two other nutrient treatments that contained phosphites plus nickel and cobalt. Heavily pruned trees and unpruned standard control trees were compared for shoot growth and canopy development.

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29 Jun 2020
Cover Crops

Can cover crops save Florida’s citrus?

Citrus greening has devastated the Sunshine State’s orange industry. Researchers and pioneering farmers see cover crops as a road to recovery.

For the last couple of decades, a tiny insect called the Asian citrus psyllid has fed on the stems and leaves of the orange trees in Florida, infecting them with bacteria that cause a lethal disease called citrus greening. The bacterial disease, huanglongbing (HLB), originated in China and has destroyed 90 percent of the state’s groves, devastating its $9 billion citrus industry.

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26 May 2020
Distribution of Liberibacter

HLB now in Kenya: Preparations to mitigate its impact on the Southern African citrus industry.

The presence of Diaphorina citri (Asian citrus psyllid, or ACP), the primary vector of the dreaded Huanglongbing disease (HLB, or Asian Citrus Greening), was first reported in east Africa in Tanzania (2015) and Kenya (2016). Surveys that CRI conducted in collaboration with local scientists, confirmed the presence of ACP in the eastern regions of Tanzania. Recently HLB, previously known to occur in some parts of Ethiopia, was detected on the east coast of Kenya (Fig. 1). The recent detection of HLB in Kenya brings it considerably closer to citrus production in Southern Africa. CRI has engaged in a process with Department of Agriculture, Land Reform and Rural Development (DALRRD) to encourage Kenyan partners to scope the possibility of containing and eradicating the disease in the region.

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