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Copyright of Revista Colombiana de Entomología is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Huanglongbing (HLB) vectored by Asian citrus psyllid (Diaphorina citri) severely affects commercial plantations of Mexican lime (Citrus aurantifolia) in the dry tropic region of Mexico. Management of Huanglongbing is based on intensive use of agronomic practices such as irrigation, nutrition, pruning, and weed, insect pest, and disease control. During 2018 to 2022, the effect of black, white, aluminum, and green plastic mulches, a white polypropylene mesh (ground cover), and bare soil (traditional system), were evaluated on D. citri and incidence-severity (I-S) of Huanglongbing, and Mexican lime yields. Trees with all types of plastic mulch had less I-S during the first 13 months of the study (35 to 40% of affected foliage) compared to bare soil (74% of tree affected). Also, plots with plastic mulches had fewer Asian citrus psyllid adults (one to 16 insects/trap/week) as compared with bare soil (11 to 28 adults). Mulched treatments had a positive effect on fruit production. After 4 years, plots with white, aluminum, green, and black plastic yielded 41.6, 40.1, 39.6, and 34.9 t/ha. Bare soil yielded only 26.6 t/ha. The cost to install plastic mulches was $526/ha. Because of that, the plastics increased yields by 50-56% and the average price of Mexican lime fruit was about $600 per ton. This production system is an economically profitable alternative to the growers to coexist with Huanglongbing in the dry tropics of Mexico. [ABSTRACT FROM AUTHOR]

A possible alternative for the control of CTV and CLas in Citrus sinensis is the use of systemic acquired resistance. The study of this mechanism requires normalizing with reference genes. Therefore, a gene expression quantification protocol using RT-qPCR was developed to evaluate the potential use of GAPDH, ACTIN, F-BOX, COX, and 18S rRNA as reference genes in citrus. A total of nine plants infected with CTV (3), CLas (3), and healthy (3) were used to select a composed sample of eight leaves/plant. An in-house protocol was developed and optimized in all its stages, varying the concentration of reagents, primers, and reaction template. Extraction of total RNA with 2% CTAB was in the range of 200-1000 ng μL-1. The reverse transcription produced on average 1069 ng μL-1 cDNA. The reference gene products GAPDH, ACTINA, and F-BOX exhibited melting curves without dimer products, Ct ≤ 28, and reaction efficiencies in the range of 90-110%. In all gene expressions, CTV infected samples had the higher Ct's (25-27) followed by healthy samples (24-25). However, GAPDH and ACTIN had the most stable gene expression (ln 1/M = 2.83), therefore these genes are proposed for normalization. The RTqPCR protocol was also specific and efficient for the CDR13 gene, putatively associated with systemic acquired resistance to CLas, which suggest its viability in resistance studies of C. sinensis/C. aurantium in response to CTV and CLas infection. [ABSTRACT FROM AUTHOR]