Plant Health and Pest Prevention Services

Sacramento, CA, United States

Plant Health and Pest Prevention Services

Sacramento, CA, United States
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Hopper J.V.,University of California at Davis | Pratt P.D.,U.S. Department of Agriculture | McCue K.F.,U.S. Department of Agriculture | Pitcairn M.J.,Plant Health and Pest Prevention Services | And 2 more authors.
Biological Control | Year: 2017

The invasive water hyacinth (Eichhornia crassipes) severely limits the ecosystem services provided by the Sacramento-San Joaquin River Delta in California, USA. As part of the biological control program in the Delta, two weevils, Neochetina bruchi and N. eichhorniae (Coleoptera: Curculionidae) and a moth, Niphograpta albiguttalis (Lepidoptera: Pyralidae), were released in the 1980s. Additionally, a planthopper, Megamelus scutellaris (Hemiptera: Delphacidae) was released in 2011. We conducted monthly surveys for one year at 16 sites throughout 1667 km2 of the Delta to determine the resulting establishment, abundance and distribution of these introduced herbivores. Morphological identifications, and partial sequencing of the mitochondrial cytochrome oxidase subunit 1 gene determined that 96.6% of the examined weevils were N. bruchi. N. eichhorniae was only recovered from two sites in the southern Delta tributaries. Densities (larvae and adult weevils per destructively sampled plant) varied spatially and temporally. Peak mean densities (averaged across August–November) decreased with increasing distance from the original release sites. Peak mean densities ranged from 0.31 to 6.31 weevils per plant. Densities averaged across sites were the lowest in June 2015 (0.54 weevils), increasing in August to 5.35 weevils, and peaking in November at 6.22 weevils. The proportion of damaged leaf area from weevil feeding increased concomitantly with weevil densities. Although N. albiguttalis was not recovered, M. scutellaris remained established at its original release site but has not dispersed into the other surveyed regions. We propose hypotheses to explain patterns in species establishment and distribution, with potential mechanisms for improved future biological control. © 2017 Elsevier Inc.

Rolshausen P.E.,University of California at Riverside | Urbez-Torres J.R.,University of California at Davis | Rooney-Latham S.,Plant Health and Pest Prevention Services | Eskalen A.,University of California at Riverside | And 2 more authors.
American Journal of Enology and Viticulture | Year: 2010

Trunk diseases diminish vineyard longevity and productivity in nearly every raisin, table, and wine grape production region worldwide. Fungi causing these diseases infect primarily through pruning wounds. One way to control these diseases is to protect pruning wounds with fungicide applications, which can be problematic because of the limited number of registered products; the difficulty for these products to control numerous taxonomically unrelated organisms; the challenge of these products to protect for the entire period of wound susceptibility; and the difficulties and costs associated with hand application of protection treatments. Our goal was to compare the susceptibility of grapevine pruning wounds to various fungi associated with trunk diseases and to evaluate the efficacy of selected fungicides to control these pathogens when applied as pruning wound protectants. The study was conducted over two consecutive years in two separate vineyards in Sonoma and Colusa counties, California. Nine pathogenic fungi were tested: Eutypa lata, Botryosphaeria dothidea, Diplodia seriata, Dothiorella viticola, Lasodiplodia theobromae, Phaeomoniella chlamydospora, Pleurostomophora richardsiae, Togninia minima, and Phaeoacremonium parasiticum. Results showed differences in the infection rates of pruning wounds by these fungi. Species of Botryosphaeriaceae were the most infectious, T. minima, P. parasiticum, P. richardsiae, and E. lata were less infectious, and Pa. chlamydospora was intermediate. Four selected fungicides were tested: 1% Topsin M, Biopaste (5% boric acid in a wound-sealing paste), 1% Cabrio EG, and Garrison. Although results highlight the difficulty of these products to control the entire spectrum of pathogens efficiently, Topsin M was overall the most efficacious product. © 2010 by the American Society for Enology and Viticulture. All rights reserved.

Jenkins D.A.,U.S. Department of Agriculture | Cline A.R.,Plant Health and Pest Prevention Services | Irish B.,U.S. Department of Agriculture | Goenaga R.,U.S. Department of Agriculture
Journal of Economic Entomology | Year: 2013

Atemoya, a hybrid between Annona squamosa (L.) and A. cherimola Miller (Annonaceae), has potential to be a major fruit crop in tropical and subtropical areas. A major setback to fruit production throughout the world is low fruit-set because of inadequate pollinator visits, typically Nitidulidae beetles. We identified beetle visitors to atemoya flowers in an orchard in Puerto Rico and used Universal moth traps to monitor the attractiveness of two commercially available Nitidulidae lures. The most common visitors to atemoya flowers were an unidentified Europs species (Coleoptera: Monotomidae), followed by Loberus testaceus (Coleoptera: Erotylidae), neither of which have been previously reported as visitors to Annona flowers. The commercial lures attracted few or no beetles when used separately, but attracted a large number of beetles, especially Carpophilus dimidiatus (Coleoptera: Nitidulidae) and Europs, when used in combination. This attraction is synergistic and increases with dose at the doses assayed (0-4 lures), and decreases over time with >50% of trap captures occurring in the first week and no beetles collected after 5 wk. This is the first report of aggregation pheromone lures in nitidulids acting synergistically to attract other species, including beetles not in the Nitidulidae. The results are discussed as they pertain to increasing fruit set, as well as the potential for altering fruit size and shape in atemoya. © 2013 Entomological Society of America.

Moran P.J.,U.S. Department of Agriculture | Pitcairn M.J.,Plant Health and Pest Prevention Services | Villegas B.,Plant Health and Pest Prevention Services
Pan-Pacific Entomologist | Year: 2016

Water hyacinth (Eichhornia crassipes (Martius) Solms-Laubach) is a non-native, invasive floating aquatic weed in the Sacramento San Joaquin Delta and associated river watersheds of northern California. Prior releases of biological control agents have not led to sustained control. The South American planthopper, Megamelus scutellaris Berg, 1883, permitted and released first in the southeastern U.S., was released at three sites in this region from 2011 to 2013, leading to establishment at one site in a pond off Willow Creek in Folsom in the American River watershed. Planthopper populations consisting of nymphs (two-Thirds or more of total counts) peaked in late summer each year between 2013 and 2015, reaching densities of six to nine planthoppers per plant by 2015. Megamelus scutellaris dispersed 50 m per year from the point of release between 2013 and 2015 and, based on degree-day estimation, were capable of producing four generations per year at the Folsom site. Proportion live leaves per plant declined by 27% in the Folsom pond between 2012 and 2015. In 2015, plants in the release pond had 40% less live above-water biomass than plants 200 meters away in a canal, into which planthoppers had dispersed in 2014-2015. This early impact of the planthopper could, however, be obscured by inter-Annual and within-site variability in plant growth. This study documents the first establishment of M. scutellaris on water hyacinth in the western U.S.

Gilbert A.J.,Plant Health and Pest Prevention Services | Riley E.G.,Texas A&M University
Pan-Pacific Entomologist | Year: 2012

Three new species of Dysphenges Horn 1894 are described from the United States: D. penrosei (Arizona), D. oblivius (Missouri, Oklahoma, Texas) and D. secretus (Texas). Habitus photographs and illustrations of male and female genitalia are presented. A taxonomic key is provided to facilitate identification of the described species of Dysphenges. A map is provided to indicate the distribution of each of the new species. © Pacific Coast Entomological Society.

Jenkins D.A.,USDA ARS Tropical Agriculture Research Station | Jenkins D.A.,Plant Health and Pest Prevention Services | Millan-Hernandez C.,USDA ARS Tropical Agriculture Research Station | Cline A.R.,Plant Health and Pest Prevention Services | And 3 more authors.
Journal of Economic Entomology | Year: 2015

Atemoya is a hybrid between Annona squamosa L. and Annona cherimola Miller (Annonaceae) and has potential to be an important fruit crop in tropical and subtropical areas. A major impediment to fruit production is low fruit set due to inadequate pollinator visits, typically, by beetles in the family Nitidulidae. We used Universal moth traps to monitor the attractiveness of two commercially available Nitidulidae lures in combination with various food attractants, including raw bread dough, apple juice, and malta beverage, a soft drink by-product of the brewing process. The most commonly trapped beetles were, in order of decreasing frequency, Carpophilus dimidiatus (F.), Brachypeplus mutilatus Erichson, Urophorus humeralis (F.) (Coleoptera: Nitidulidae), and Europs fervidus Blatchley (Coleoptera: Monotomidae). All traps, except the unbaited control traps, caught beetles. In a previous study, we found that combining two commercial lures had a synergistic effect on the attraction of these beetle species. In this study, the addition of food attractants increased the number of beetles trapped compared with traps baited with only the commercial lures. Also, food attractants appear to be key in attracting U. humeralis; only one U. humeralis individual of the 206 caught during the experiment was trapped without a food attractant. The variation between the number of beetles caught in traps containing the same treatments was high and may explain the erratic results reported in other studies of pollination in Annona spp. The results are discussed with respect to the use of nitidulid lures and food attractants to increase fruit set in atemoya and other Annonaceae. © Published by Oxford University Press on behalf of Entomological Society of America 2015.

Two new species of Cryptocephalus Geoffroy, 1762 are described from the Baja California peninsula, Mexico: C. drewi sp. nov., and C. incognitus sp. nov., with illustrations of the male genitalia presented for the former. Specimens previously reported as C. sanguinicollis nigerrimus Crotch, 1874 from the Baja California peninsula were determined to represent C. drewi, while specimens previously reported as C. vapidus White, 1968 were identified as C. californicus Clavareau, 1913. As a result, C. sanguinicollis nigerrimus and C. vapidus are removed from the list of chrysomelid species believed to occur in the Baja California peninsula. A non-type male specimen of C. californicus is described, and differences between the male and female are provided. Color habitus photographs and information on distribution are provided for all three species.

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