Abstract

Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae Kuwana) is an invasive pest that primarily infests crapemyrtles (Lagerstroemia spp.), along with a few other economically important plants in the U.S. Current management practices predominantly rely on neonicotinoid insecticides, which are structurally similar to nicotine and act as agonists at nicotinic acetylcholine receptors (nAChRs), disrupting insect nervous systems. However, the specific impact of these insecticides on CMBS herbivory performance remains unclear. This study combines pectinolytic enzyme detection and electrical penetration graph (EPG) techniques to investigate nicotine’s impact on CMBS salivation and ingestion. CMBS feeding assays were conducted on agarose plates containing various concentrations of pectin and nicotine. The enzyme detection experiments revealed CMBS salivation involves pectinesterase and polygalacturonase secretion, unaffected by nicotine. Consistent with these findings, EPG analysis confirmed salivation (waveform E1) occurred in nicotine-containing agarose. Unexpectedly, phloem sap ingestion (waveform E2) was absent when nicotine was added to the agarose, indicating selective inhibition of CMBS ingestion. These findings suggest nAChRs specifically regulate sap ingestion in CMBS, but not salivation and other feeding behaviors. These insights into nicotine and neonicotinoid insecticide action on CMBS could inform precision insecticide application in IPM programs, potentially enhancing control efficacy while reducing environmental impact.

Species used in this study: Crapemyrtle bark scale (Acanthococcus lagerstroemiae Kuwana).

Chemicals used in this study: Agarose (Bio-Rad Laboratories), pectin (MP Biomedicals), nicotine (Sigma-Aldrich), sucrose (Domino Foods Inc.), glutamine (Thermo Fisher Scientific), ruthenium red (Enzo Life Sciences Inc.).

Abstract

Exponential population growth pressures the agriculture industry to provide fresh foods to both rural and urban areas. GREENBOX technology, based on Controlled Environment Agriculture (CEA) principles, addresses this challenge by optimizing conditions for leafy green crops. It integrates into urban infrastructure to mitigate the effects of urbanization on fresh food availability. GREENBOX controls environmental factors like temperature, humidity, light, and nutrient delivery to enhance crop growth. Given that artificial lighting is a major energy consumer in CEA, this study explored different photoperiods to improve energy efficiency. Lactuca sativa ‘Rex Butterhead’ lettuce was grown under three photoperiods: 16-hour light/8-hour dark (control), 14-hour light/10-hour dark, and 12-hour light/12-hour dark. Biomass parameters, including fresh and dry weight, leaf area, leaf count, and chlorophyll concentration, were measured. While all treatments produced viable crops above the expected harvest weight, the 16-hour photoperiod caused statistically significant (p < 0.001) differences in fresh weight, dry weight, leaf count, Specific Leaf Area (SLA), and Leaf Area Index (LAI) compared to the shorter photoperiods. No significant differences were found between the 12-hour and 14-hour treatments. These results suggest that photoperiod adjustments could enhance the efficiency and productivity of GREENBOX units for urban agriculture.

Species used in this study: Rex ‘Butterhead’ lettuce, Latuca sativa L.

Abstract

The boxwood blight pathogens Calonectria pseudonaviculata (Cps), and C. henricotiae (Che), produce microsclerotia (ms) on and in leaf tissue and conidia in sticky masses that can be spread by equipment and tools. We evaluated the effects of sanitizers on conidia, excised ms or all Cps life stages in 4-mm-d leaf disks. Leaf disks and excised ms were exposed to sanitizers or water for 3 to 180 min (disks), or 0.5 to 30 min (ms), wicked dry and placed onto half-strength potato dextrose agar (PDA) to determine viability. Conidia were loaded onto a filter, exposed to alcohol concentrations for between 2 sec to 2 min and rinsed with water. Filters were backwashed with air to transfer conidia onto water agar and the percent germination was counted after 24 h. Cps in leaf disks was killed within 10 – 12 min for 70% ethanol and between 2 – 3 h for 0.525% NaOCl. Chlorophenol did not eliminate Cps from tissue. Individual ms were killed by 70% ethanol in 4 min. However, ms exposed to 0.525% NaOCl or 0.05% chlorophenol for 30 min retained viability. Conidia mortality of Cps and Che exposed to 10, 25, 40 and 70% ethanol was strongly influenced by concentration and duration of exposure. Most importantly, conidia of Cps and Che died after a 5 sec exposure to either 70% ethanol or isopropanol, and there were no differences between alcohols. Ethanol and isopropanol can quickly and inexpensively disinfest tools and contaminated surfaces.

Species used in this study: Boxwood (Buxus × ‘Green Velvet’); Calonectria henricotiae. Gehesquière, Heungens and J.A. Crouch; C. pseudonaviculata (Crous et al.) L. Lombard et al.

Chemicals used in this study: Ethanol; isopropyl alcohol; sodium hypochlorite (bleach); Chlorophenol (Lysol®); Polyethylene glycol sorbitan monolaurate (Tween 20).

Abstract

Cutting propagation provides uniform plants that retain the original characteristics of the donor. This method requires forming adventitious roots. Our previous studies indicate that semi-lignified stem cuttings of American chestnut [Castanea dentata (Marshall) Borkh.] and yellow camellia (Camellia nitidissima Chi.) exhibit low levels of the rooting-promoting hormone indole-3-acetic acid and high levels of other hormones that inhibit rooting induction and development. Additionally, their hormone distribution between leaves and stems differs from that of easy-to-root poplar. This unfavorable endogenous hormone profile may contribute to the recalcitrance of rooting in American chestnut and yellow camellia cuttings. In this study, we found that the vascular cambium region in American chestnut cuttings was the least active and most condensed, with clusters of active cell division not presenting until 48 days after excision and auxin induction. American chestnut stems possess a closed sclerenchyma ring, while sclerenchymata in yellow camellia, poplar hybrids (Populus spp.), and weeping willow (Salix babylonica L.) cuttings are dispersed. Promoter analysis of an adventitious root-promoting gene, AINTEGUMENTA, showed that the number of auxin-responsive cis-elements in poplar is at least three times greater than in American chestnut, likely contributing to the contrasting rooting response with auxin between the two species. Compared to 1-naphthaleneacetic acid, a slow-release synthetic auxin, 4-chlorophenoxyacetic acid-l-tryptophan-OMe, induced more adventitious roots in American chestnut cuttings.

Species used in this study: American chestnut [Castanea dentata (Marshall) Borkh.], poplar hybrids ‘Ogy’ [Populus × euramericana (Dode) Guinier] and 717-1B4 (P. tremula L. × P. alba L.), weeping willow (Salix babylonica L.), yellow camellia (Camellia nitidissima Chi.).

Chemicals used in this study: 1-Naphthaleneacetic acid (NAA), 4-chlorophenoxyacetic acid–l-tryptophan-OMe.