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.
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.
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.
In this study, newly identified small molecules were examined for efficacy against ‘Candidatus Liberibacter asiaticus’ in commercial groves of sweet orange (Citrus sinensis) and white grapefruit (Citrus paradisi) trees. We used benzbromarone and/or tolfenamic acid delivered by trunk injection. We evaluated safety and efficacy parameters by performing RNAseq of the citrus host responses, 16S rRNA gene sequencing to characterize citrus-associated microbial communities during treatment, and qRT-PCR as an indirect determination of ‘Ca. L. asiaticus’ viability. Analyses of the C. sinensis transcriptome indicated that each treatment consistently induced genes associated with normal metabolism and growth, without compromising tree viability or negatively affecting the indigenous citrus-associated microbiota.
Beneficial microorganisms are becoming increasingly important in the biological control of citrus pests, as a complement to the release of auxiliary insects. Proof of this is the research carried out by Koppert Spain, which aims to confirm the efficacy of an entomopathogenic fungus that could help control Trioza erytreae, one of the insects that transmits huanglongbing (HLB), or citrus greening. “Koppert’s objective is to develop a biological solution that may be available to producers if the insect that transmits the HLB arrived in Spain,” said Javier Calvo, researching entomologist at Koppert, in the framework of a Citrus Technical Conference held in El Rompido (province of Huelva) and Palma del Río (province of Cordoba).
Florida citrus growers have always understood the importance of soil health and the positive influence of microbial activity and diversity in production. As citrus greening (also known as HLB) has spread, reducing production by more than 70%, interest in how these tiny organisms can improve root health is increasing. Research showing the disease, which is spread by the Asian citrus psyllid, can reduce citrus fibrous-root density by 30% to 50% before symptoms become visible above ground only intensifies the interest to learn more.
CORONA — A Southern California quarantine zone has been expanded in an effort to stop the spread of a disease that threatens the state’s multi billion-dollar citrus industry.
Diane Nelson, UC Davis
https://phys.org
In an orange grove outside Exeter, California, workers climb aluminum ladders to pick fruit with expert speed. California produces 80 percent of the nation’s fresh oranges, tangerines and lemons, most of it in small Central California communities like these.
“This may be the last place in the world where you can still grow citrus,” says farmer Richard Bennett, reaching high to pull an orange from a tree. He peels it in two long ribbons, and the scent of zest fills the air. “Citrus is so important to our health and economy, and it’s threatened by a devastating disease.”