Range-wide population genomics of the Mexican fruit fly: Toward development of pathway analysis tools.

Recurrently invading pests provide unique challenges for pest management, but also present opportunities to utilize genomics to understand invasion dynamics and inform regulatory management through pathway analysis. In the southern United States, the Mexican fruit fly Anastrepha ludens is such a pest, and its incursions into Texas and California represent major threats to the agricultural systems of those regions. We developed a draft genome assembly for A. ludens, conducted range-wide population genomics using restriction site-associated DNA sequencing, and then developed and demonstrated a panel of highly differentiated diagnostic SNPs for source determination of intercepted flies in this system. Using 2,081 genomewide SNPs, we identified four populations across the range of A. ludens, corresponding to western Mexico, eastern Mexico/Texas, Guatemala/Belize/Honduras, and Costa Rica/Panama, with some intergradation present between clusters, particularly in Central America. From this population genomics framework, we developed a diagnostic panel of 28 highly differentiated SNPs that were able to recreate the genomewide population structure in this species. We demonstrated this panel on a set of test specimens, including specimens intercepted as part of regular trapping surveillance in Texas and California, and we were able to predict populations of origin for these specimens. This methodology presents a highly applied use of genomic techniques and can be implemented in any group of recurrently invading pests.

Pseudocromata, a new genus of Ochlerini based on a new species from Ecuador (Pentatomidae: Discocephalinae).

The tribe Ochlerini was defined by Rolston (1981) based on the position of abdominal trichobothria (lateral to the spiracles), insertion of the labium well behind the apex of the head (usually in line with the eyes), and the superior surface of the distal metatarsomere in females excavate or flattened. Rolston's (1992) revision of the tribe included 28 genera. With subsequent additions there are now either 33 or 35 genera depending on the inclusion or exclusion of Melambyrsus Breddin (listed as nomen dubium by Rolston 1992) and Candeocoris Roell & Campos (2015) which has character-states intermediate between Ochlerini and Discocephalini. With few exceptions the members of the tribe are inornately colored, typically shades of black, brown or tan Campos & Grazia (2006). Exceptions are species in the genera Cromata Rolston and the aforementioned Candeocoris which have colorful blotches on the scutellum and corium.

Phylogeographic Structure in Anastrepha ludens (Diptera: Tephritidae) Populations Inferred With mtDNA Sequencing.

Anastrepha ludens (Loew) (Diptera: Tephritidae), the Mexican fruit fly, is a major pest of citrus and mango. It has a wide distribution in Mexico and Central America, with infestations occurring in Texas, California, and Florida with origins believed to have been centered in northeastern Mexico. This research evaluates the utility of a sequence-based approach for two mitochondrial (COI and ND6) gene regions. We use these markers to examine genetic diversity, estimate population structure, and identify diagnostic information for A. ludens populations. We analyzed 543 individuals from 67 geographic collections and found one predominant haplotype occurring in the majority of specimens. We observed 68 haplotypes in all and see differences among haplotypes belonging to northern and southern collections. Mexico haplotypes differ by few bases possibly as a result of a recent bottleneck event. In contrast to the hypothesis suggesting northeastern Mexico as the origin of this species, we see that specimens from two southern collections show high genetic variability delineating three mitochondrial groups. These data suggest that Central America is the origin for A. ludens. We show that COI and ND6 are useful for phylogeographic studies of A. ludens.

Comparison of torula yeast and various grape juice products as attractants for Mexican fruit fly (Diptera: Tephritidae).

Early research investigating attractants for the Mexican fruit fly, Anastrepha ludens Loew, during the 1930s indicated that fermentation products were effective attractants for Mexican fruit flies and other tropical Tephritidae, but that attraction to fruit components was only of academic interest. Tests reported here were carried out on populations of Mexican fruit flies from 2004 to 2011. Trapping experiments carried out at sites in the states Nuevo Leon and San Luis Potosi compared grape juice, reconstituted grape concentrate and powdered grape mixes, and torula yeast extract in orchards at each site. The Nuevo Leon orchard was mixed with alternate rows of pears and surrounded by alternate hosts. The San Luis Potosi site was surrounded by other orange orchards or nonhosts. Each test was run for at least 10 mo and included highest and lowest trapping periods. Results showed that grape juice captured the most total flies and had the fewest samples with zero flies. However, in the series of experiments, each product had the most captures in at least one experiment. Hydrolyzed torula was superior in one of the six experiments. In five of the tests, polyethylene glycol was tested as an additive to the grape products but never improved capture rate compared with the product without the additive. These results indicate that grape juice is superior to grape concentrate or powder and grape juice is at least equal to torula yeast hydrolysate for trapping pest populations of Mexican fruit flies in commercial citrus orchards.

Evaluation of the efficacy of the methyl bromide fumigation schedule against Mexican fruit fly (Diptera: Tephritidae) in citrus fruit.

Methyl bromide fumigation is widely used as a phytosanitary treatment. Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae), is a quarantine pest of several fruit, including citrus (Citrus spp.), exported from Texas, Mexico, and Central America. Recently, live larvae have been found with supposedly correctly fumigated citrus fruit. This research investigates the efficacy of the previously approved U.S. Department of Agriculture-Animal and Plant Health Inspection Service treatment schedule: 40 g/m3 methyl bromide at 21-29.4 degrees C for 2 h. Tolerance ofA. ludens to methyl bromide in descending order when fumigated in grapefruit (Citrus X paradisi Macfad.) is third instar > second instar > first instar > egg. Two infestation techniques were compared: insertion into fruit of third instars reared in diet and oviposition by adult A. ludens into fruit and development to the third instar. Inserted larvae were statistically more likely to survive fumigation than oviposited larvae. When fruit were held at ambient temperature, 0.23 +/- 0.12% of larvae were still observed to be moving 4 d postfumigation. Temperatures between 21.9 and 27.2 degrees C were positively related to efficacy measured as larvae moving 24 h after fumigation, pupariation, and adult emergence. Coating grapefruit with Pearl Lustr 2-3 h before fumigation did not significantly affect the proportion of third instars moving 24 h after fumigation, pupariating, or emerging as adults. In conclusion, fumigation with 40 g/m3 methyl bromide for 2 h at fruit temperatures >26.7 degrees C is not found to be inefficacious for A. ludens. Although a few larvae may be found moving >24 h postfumigation, they do not pupariate.

Comparison of two synthetic food-odor lures for captures of feral Mexican fruit flies (Diptera: Tephritidae) in Mexico and implications regarding use of irradiated flies to assess lure efficacy.

Feral Mexican fruit flies, Anastrepha ludens (Loew) (Diptera: Tephritidae), were trapped in a citrus orchard in Mexico by using two types of synthetic food-odor lures, the AFF lure (Anastrepha fruit fly lure, APTIV, Inc., Portland, OR) and the BioLure (two-component MFF lure, Suterra LLC, Inc., Bend, OR). In Multilure traps (Better World Manufacturing, Inc., Miami, FL) containing water, BioLures captured about the same numbers of flies as AFF lures. In Multilure traps containing antifreeze solution, BioLures captured 2 and 5 times more flies than AFF lures in two experiments. BioLures, and AFF lures did not differ in attractiveness when used on sticky traps (Intercept trap, APTIV, Inc.; and sticky cylinder trap). Multilure traps captured >4 times as many flies as sticky traps with the exception that captures of females did not differ between Multilure and sticky traps baited with AFF lures. The percentage of females captured in Multilure traps was greater when traps were baited with BioLures compared with AFF lures, but the reverse was true for sticky traps. Sticky cylinder traps captured a higher percentage of females than Multilure traps. The most effective trap/lure combination was the Multilure trap baited with BioLure and antifreeze. In comparison with tests of these two lures in Texas, results were similar for Multilure traps, but they differed for sticky cylinder traps in that AFF lures were consistently more attractive than BioLures in Texas, but not in Mexico.

Nontarget impact of spinosad GF-120 bait sprays for control of the Mexican fruit fly (Diptera: Tephritidae) in Texas citrus.

Bait sprays containing the toxicant spinosad (GF-120) were applied to citrus groves in the Rio Grande Valley of Texas where Mexican fruit flies were detected in surveillance traps. The sprays were applied as a supplement to a continuous sterile insect release program. Sterile fly captures were 47-63% lower in the treated groves compared with control groves. Eight of 10 secondary pest populations declined in the test groves subsequent to spray applications, but they also declined in the control groves, suggesting that the decline was a seasonal phenomenon rather than a result of the bait sprays. Citrus whitefly, Dialeurodes citri (Ashmead), populations increased modestly and citrus blackfly, Aleurocanthus woglumi (Ashby), populations remained unchanged compared with pretreatment levels. Thus, no outbreaks of secondary pests occurred as a result of the spinosad bait sprays in this instance, as has been reported for malathion bait sprays in citrus. The bait sprays had no detectable effect on populations of specific indicator species of parasitoids (including Aphytis spp. and Comperiella bifasciata Howard), or on numbers of beneficial insects in general, in the treated groves.

Reproductive phenology of the Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae) in the Sierra Madre Oriental, Northern Mexico / Fenologia reprodutiva de Anastrepha ludens (Loew) (Diptera: Tephritidae) na Serra Madre Oriental, Norte do México

Em seu hábitat nativo no Norte do México, Anastrepha ludens (Loew) é normalmente bivoltina, embora possa ocorrer uma terceira geração em alguns anos. As moscas entram em diapausa principalmente no estádio pupal, emergindo em janeiro-fevereiro. Essas moscas adultas ovipositam no cultivo de primavera do citrus selvagem Sargentia greggii (S. Wats.). O pico primário de população ocorre do final da primaveraaté o início do verão (em anos excepcionais, ocorrem picos separados na primavera e no verão). A dissecção das fêmeas demonstrou que a maioria das moscas que ocorrem no pico de primavera são imaturas reprodutivamente, indicando a emergência de novos adultos. A atividade se reduz ao final do verão, ou pelo menos poucas moscas são coletadas nessa fase. No outono ocorre a ressurgência da atividade dos adultos. Entretanto, ao contrário do que ocorre no pico de primavera, a dissecção das fêmeas revelou que a grande maioria das fêmeas adultas de outono já estão grávidas, indicando que elas permanecem na população do início do verão, ao invés de surgirem novas fêmeas. As fêmeas de outono ovipositam em outubro-novembro, produzindo a populacão que entra em diapausa e emerge em janeiro-fevereiro.

In its native habitat in northern Mexico, Anastrepha ludens (Loew) is normally bivoltine although a third generation is achieved in some years. The flies overwinter mainly in the puparial stage,emerging in January-February. These flies oviposit in the spring crop of a wild citrus, Sargentia greggii (S. Wats.). The primary population peak follows in late spring to early summer (in exceptional years, separate peaks in spring and summer). Dissection of the females demonstrated that most of the flies inthe spring peak are reproductively immature, indicating emergence of new adults. Activity subsides in late summer, or at least, few flies can be trapped at this time. Then in the fall there is a resurgence of adult activity. However, in contrast to the spring peak, dissection revealed that the great majority of thefall adult females are already gravid, indicating that they are carry-overs from the early summer population, rather than new recruits. The fall adults oviposit in October-November, producing the overwintering population that will emerge as adults in January-February.