Two 15-d nutrient balance trials were conducted using a total of 32 weanling barrows (averaging 6.8 kg, 26 d). The effect of the addition of 15 or 250 ppm Cu (as CuSO4.5H2O) to diets containing 0 or 5% added animal fat on nutrient utilization, digestive enzyme activities, and tissue mineral levels in weanling pigs was investigated. In each trial, four groups of four littermate barrows were randomly assigned to one of four treatments in a 2 x 2 factorial arrangement. The addition of 250 ppm Cu improved apparent fat digestibility and apparent nitrogen retention (P < .02). The addition of 5% fat increased apparent fat digestibility (P < .01). There were no Cu x fat interactions (P > .10) for any of the digestibility indices measured. The addition of 250 ppm of Cu stimulated small intestinal lipase (P < .01) and phospholipase A (P < .05) activities but had no effect (P > .10) on pancreatic lipase or phospholipase activities and no effect on trypsin, chymotrypsin, or amylase activities in the small intestine or the pancreas. The addition of 250 ppm Cu to the diet increased Cu (P < .001) in plasma, liver, and kidney and decreased Fe in plasma (P < .05) and liver (P < .02). The addition of 5% fat increased Fe in kidney (P < .05) and heart (P < .08). Copper x fat interactions were observed for spleen Ca (P < .01), Mg (P < .08), Na (P < .05), and K (P < .08) and spleen weight (P < .05). In additional in vitro assays, increased Cu concentrations tended to consistently stimulate purified porcine pancreatic lipase activity (linear, P < .01) but not purified porcine pancreatic phospholipase A activity (P > .10). The results from this study indicate that 250 ppm Cu stimulated intestinal lipase and phospholipase A activities, leading to an improvement of dietary fat digestibility in weanling pigs.

Strains of Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) of cucurbits, can be assigned to two groups, I and II. The natural association of group I and II strains with different cucurbit species suggests host preference; however, there are no direct data to support this hypothesis under field conditions. Hence, the objective of this study was to assess differences in the prevalence of group I and II A. citrulli strains on cucurbit species in the field. From 2017 to 2019, we used group I and II strains to initiate BFB outbreaks in field plots planted with four cucurbit species. At different times, we collected symptomatic tissues and assayed them for group I and II strains using a group-specific PCR assay. Binary distribution data analysis revealed that the odds of melon, pumpkin, and squash foliage infection by group I strains were 21.7, 11.5, and 22.1 times greater, respectively, than the odds of watermelon foliage infection by the group I strain (P < 0.0001). More strikingly, the odds of melon fruit infection by the group I strain were 97.5 times greater than watermelon fruit infection by the same strain (P < 0.0001). Unexpectedly, some of the group II isolates recovered from the 2017 and 2019 studies were different from the group II strains used as inocula. Overall, data from these experiments confirm that A. citrulli strains exhibit a preference for watermelon and melon, which is more pronounced in fruit tissues.

Agronomic crops engineered with resistance to 2,4-D or dicamba have been commercialized and widely adopted throughout the United States. Due to this, increased use of these herbicides in time and space has increased damage to sensitive crops. From 2014 to 2016, cucumber and cantaloupe studies were conducted in Tifton, GA to demonstrate how auxinic herbicides (2,4-D or dicamba), herbicide rate (1/75 or 1/250 field use), and application timing (26, 16, and 7 d before harvest (DBH) of cucumber; 54, 31, and 18 DBH of cantaloupe) influenced crop injury, growth, yield, and herbicide residue accumulation in marketable fruit. Greater visual injury, reductions in vine growth, and yield loss were observed at higher rates when herbicides were applied during early-season vegetative growth compared to late-season with fruit development. Dicamba was more injurious in cucumber while cantaloupe responded similarly to both herbicides. For cucumber, total fruit number and relative weights were reduced (16 to 19%) when either herbicide was applied at the 1/75 rate 26 DBH. Cantaloupe fruit weight was also reduced 21 and 10% when either herbicide was applied at the 1/75 rate 54 or 31 DBH, respectively. Residue analysis noted applications closer to harvest were more likely to be detectable in fruit than earlier applications. In cucumber, dicamba was detected at both rates when applied 7 DBH, while in cantaloupe it was detected at both rates when applied 18 or 31 DBH in 2016 and at the 1/75 rate applied 18 or 31 DBH in 2014. Detectable amounts of 2,4-D were not observed in cucumber but were detected in cantaloupe when applied at either rate 18 or 31 DBH. While early season injury will more likely reduce cucumber or cantaloupe yields, the quantity of herbicide residue detected will be most influenced by the time interval between the off-target incident and sampling.

Root-knot nematode (Meloidogyne spp.) exhibits a substantial problem in pepper production, causing reduction in yield throughout the world. Continued assessment for root-knot resistance is important for developing new resistance cultivars. In this study, the effect of Me and N genes on the penetration and reproduction of M. incognita race 3, M. arenaria race 1, M. javanica, and M. haplanaria was examined under controlled greenhouse conditions using susceptible and resistant pepper lines/cultivars (Mellow Star, Yolo Wonder B, Charleston Belle, HDA-149, HDA-330, PM-217, and PM-687) differing in the presence or absence of resistant genes. The penetration and resistance responses of these pepper lines differed depending on the nematode species. More second-stage juveniles penetrated roots of susceptible control cultivar Mellow Star than roots of resistant cultivars/lines. Although, there was no significant difference in the nematode penetration among resistant lines 1 and 3 days after inoculation (DAI), variability in the penetration of M. incognita, M. javanica, and M. haplanaria was observed 5 DAI. This demonstrates the variability among different nematode resistance genes to invasion by Meloidogyne spp. Based on nematode gall index (GI) and reproduction factor (RF), Charleston Belle, HDA-149, PM-217 and PM-687 showed very high resistance (GI < 1 and RF < 0.1) to M. incognita, M. arenaria, and M. javanica. Although, all the Meloidogyne-resistant pepper lines evaluated were resistant to M. javanica and M. haplanaria, the susceptible cultivar Mellow Star was a good host for all nematode species having an RF ranging from 8.1 to 34.7. The N, Me1, and Me3 genes controlled resistance to reproduction of all species of Meloidogyne examined.