Huanglongbing (HLB) was first discovered in Florida in 2005. It can now be found in all counties in the state where commercial citrus production takes place. HLB is a bacterial disease that is transmitted by the Asiatic citrus psyllid. HLB negatively affects citrus producers in several ways, including reduced yield, increased grove maintenance costs, and increased tree mortality. The research presented in this article suggests that another consequence of HLB is its adverse effect on the willingness of producers to invest in new plantings. Reduced plantings imply reduced fruit production in the future.
Thomas H. Spreen, Jean-Paul Baldwin and Stephen H. Futch
Stephen H. Futch, James H. Graham and Larry W. Duncan
Florida citrus groves of sweet orange (Citrus sinensis), tangerines (Citrus reticulata), and grapefruit (Citrus paradisi) experience an annual tree loss of 3% to 4% due to various causes of tree decline. Commonly used tree removal methods in Florida include “pushing,” which lifts most of the root system completely out of the soil, or “clipping,” which shears the tree off above the soil line leaving the tree stump and root system in place. Several operational and economic advantages and disadvantages exist for both tree removal systems. There are also potential problems with citrus resets that can occur due to foot rot (Phytophthora nicotianae) and citrus nematodes (Tylenchulus semipenetrans) that remain in the soil after tree removal. To investigate reset tree performance after “pushing” versus “clipping,” a study was conducted in three groves representative of three production regions in Florida to compare the impact of tree removal method on the pest/pathogen status and growth of resets over a period of 4 years. Based on the findings, tree removal by “pushing” or “clipping” appears to have minimal effect on subsequent pest and pathogen status and performance of citrus resets. Therefore, the method of tree removal should depend primarily on operational and economic considerations.
Ariel Singerman, Marina Burani-Arouca and Stephen H. Futch
The Florida citrus industry has been enduring the impact of citrus greening since 2005. The disease has been the main driver for the state’s citrus production to plummet by 80% in the past 13 years, causing the industry to downsize drastically. Planting new groves is key to ensuring a supply of fruit for processors and packinghouses to stay in business. However, a key question is whether it makes economic sense to plant a new grove in the current environment. We estimate the establishment and production costs for a new grove under endemic Huanglongbing (HLB; citrus greening) conditions for three different tree planting densities under different market conditions and examine their profitability. Our results show that establishing a new grove with a tree density similar to that of the state’s average is not profitable under current market conditions. However, greater tree densities are profitable despite the greater level of investment required.
Giuseppe Vanella, Masoud Salyani, Paolo Balsari, Stephen H. Futch and Roy D. Sweeb
The main objective of this study was to evaluate the suitability of the DEIAFA drift test bench system (Dipartimento di Economia e Ingegneria Agraria, Forestale e Ambientale; University of Torino, Italy) for assessing drift potential of a citrus (Citrus sp.) herbicide applicator. The study involved testing the effects of spray drift shield, nozzle type, and ground speed on drift potential of the applications. It was carried out in randomized block design within a split-split-plot experiment with five replications. A computational analysis procedure for evaluation of deposit values, measured along the test bench, was developed to compare the treatments in terms of a drift potential index (DPI). The methodology provided repeatable results. Among the treatments, ground speed was the main factor affecting the DPI. Both nozzle types tested [flat fan extended range nozzle (XR) and wide-angle deflector nozzle (TT)] showed higher DPI at faster speed. Decreasing the ground speed from 6.0 to 3.0 km·h−1 decreased the drift potential on average ≈35%. The performance of XR nozzle was improved by the presence of spray drift shield (27% reduction in DPI). However, the shield did not affect the drift potential of the TT nozzle significantly. The results were significantly affected by the wind velocity normalized by its direction relative to the sprayer travel; therefore, the tests should be carried out in relatively calm wind conditions, as much as possible.