Field studies were conducted to evaluate the effect of mating disruption on the mating success of the gypsy moth, Lymantria dispar (L), in low-density populations. The gypsy moth is an insect pest of hardwood forests in many regions of the world. The discovery of the sex pheromone disparlure (cis-7,8-epoxy-2-methyloctadecane) produced by females marked the start of a new era in the control and management of gypsy moth populations. Sex pheromones, like disparlure, have been used for detecting new populations, monitoring the spread of populations and for population control based on the disruption of mating communication. Although mating disruption has been used against populations of insect pests in agricultural and forest systems, considerable information about the use of this method for managing gypsy moths is still lacking. Studies, therefore, were designed and carried out specifically to improve current understanding of the mechanism of mating success, to evaluate existing techniques for mating disruption, and to develop methods that would improve the application of pheromone used for mating disruption so as to reduce the costs associated with the use of this management tactic. The first study was conducted to compare the mating success and mortality of gypsy moth females in low-density populations in Virginia and Wisconsin because of differences, which have been observed in the population dynamics and the impact of management strategies between these two states. The results suggested that the higher rate of population spread in Wisconsin might be due to the increased mating success of females compared with Virginia, which may be due in part to increased long-distance dispersal of males and increased longevity of females. The effect of artificial pheromone applied at various doses and formulations on mating success in low-density gypsy moth populations also was studied. Dose-response relationships were obtained for pheromone doses ranging from 0.15 to 75 g a.i./ha. The doses of 37.5 and 15 g a.i./ha of pheromone were shown to effectively disrupt mating and, therefore, have been recommended for operational use. The results also showed that the disruption of mating and attraction of males to pheromone-baited traps as a result of application of pheromone formulated in plastic flakes (Disrupt® II, Hercon Environmental, Emigsville, PA) was stronger and lasted longer than for the pheromone formulated as microcapsule (3M Canada Co., London, Ontario, Canada) and in liquid (Shin-Etsu Chemical Co. Ltd, Tokyo, Japan). Another study was carried out to improve the use and efficacy of the pheromone for mating disruption by reducing the amount of pheromone that was sprayed and the flight distance during aerial application. This study showed that in mountainous landscapes the effect of disparlure along the valley between mountains could be observed at a larger distance (633 ± 63 m) from the treated area than across the valley (104 ± 22m). In a relatively flat area, the effective distance for mating disruption was similar to the effective distance across the valley in a mountainous area (67 ± 17m). These dispersal characteristics of the pheromone provided further evidence that it could be used effectively in mating disruption treatments. Finally, a portable Electroantennogram (EAG) device was evaluated for its ability to detect disparlure sprayed for mating disruption in gypsy moth populations. The study found no relationship between the dose of artificial airborne pheromone and response of gypsy moth antenna as measured by the voltage ratio. The inability to detect differences between airborne pheromone concentrations in the plots treated for mating disruption might have been due to high variability among antennae and also by the inability of the EAG device to detect the low concentration of airborne pheromone used operationally for mating disruption. Further studies are required to improve the sensitivity of the portable EAG device before it can be recommended for use in the field. / Ph. D.

The populations of aphidophagous insects in low-spray and conventional programs were surveyed in Virginia apple orchards. Two sampling methods were utilized;aphid colony collection and beating tray collection. The low-spray blocks employed the use of mating disruption for control of the key direct pests, codling moth, Cydia pomonella (Linnaeus), and leafrollers. The abundance and diversity of aphid predators in low-spray mating disruption programs and conventionally controlled apple orchards was compared. Both sampling methods suggested that aphid predators were more plentiful in the mating disruption blocks. Several mating disruption blocks were found to accumulate significantly more predator-days and diversity than the matched control blocks. The reduction of insecticide input into the low-spray blocks may have allowed higher populations of aphidophagous insects to occur. Aphid populations in mating disruption blocks sometimes declined faster and had less resurgence than those in the conventionally controlled blocks. The tufted apple bud moth (TABM), Platynota idaeusalis (Walker), populations in four apple orchards in Winchester, Virginia, were compared for resistance to azinphosmethyl. These orchards were suspected by the growers to have resistant populations of TABM. Pheromone traps with insecticide incorporated into the adhesive were used to collect and test the moths. The results were not analyzed due to the low number of moths collected and high variability in mortality. / Master of Science

Licentiatavhandling (sammanfattning) Alnarp : Sveriges lantbruksuniversitet. / Härtill 2 uppsatser.

The pink hibiscus mealybug (PHM), Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae) was investigated with regard to damage caused to hibiscus by feeding, dispersal of nymphs, evaluation of management tactics, and the use of sex pheromone based monitoring in southern Florida from 2005 to 2008. Understanding the ability of PHM to locate and colonize new hosts, and the response of hosts is essential to optimized monitoring and management strategies. Investigation of the onset and severity of PHM feeding symptoms by Hibiscus rosa-sinensis L. showed that severity of symptoms differed among cultivars and that PHM were found on plants that did not exhibit feeding symptoms. Aerially dispersing PHM were predominantly first instars. Dispersal occurred with a diel periodicity that peaked between 14:00 and 18:00 h and was significantly influenced by mean wind speed. Initial infestation with 5, 10, or 20 PHM adult females had no significant affect on the number of dispersing individuals captured from hibiscus plants and PHM were captured at 50 m from infested source plants. The effects of mating disruption, the insecticide (dinotefuran), the parasitoid, Anagyrus kamali (Moursi), and the predator, Cryptolaemus montrouzieri (Mulsant) on PHM on hibiscus plants in screened field cages were evaluated. The total number of mealybugs captured in sticky band and pheromone traps during the study was reduced by dinotefuran and the predator. At the end of the study, the number of nymphs recovered from hibiscus terminals was reduced by the dinotefuran, predator and parasitoid treatments. Field experiments showed that the time of day during which male PHM were captured in pheromone traps in May and September was crepuscular, with most captures occurring from 18:00 to 21:00 h. Significantly more males were captured in traps placed in non-host trees at an elevation of 2 m above the ground than 6 m, and more males were captured in traps placed within host plants than in those 3 m upwind. Pheromone traps placed in hibiscus treated with soil applied dinotefuran or left untreated captured equal numbers of males during the 3 wk prior to treatment and during the 12 wk after treatment. Release of parasitoids at residential sites did not have a significant effect on the total number of males captured in sex pheromone traps over 18 mo. The number of mealybugs found at both parasitoid release and untreated sites were highly variable and corresponded with males captured in sex pheromone traps, as high and low levels of mealybugs corresponded with high and low levels of males captured. The number of males captured in pheromone traps during a two week survey at residential sites in May were a strong predictor of subsequent captures in 2006 (r2 = 0. 712), but not 2007 (r2 = 0.019). The relationship between PHM populations and males captured in sex pheromone traps was influenced by a multitude of factors that can impact the ability of traps to accurately reflect populations at a given location. Pheromone traps have the potential to provide meaningful information towards monitoring and mitigating risk from PHM. The contributions of this dissertation towards optimizing PHM sex pheromone monitoring, as well as facets of PHM monitoring that have yet to be resolved are discussed. / Ph. D.

Swede midge (Contarinia nasturtii, Diptera: Cecidomyiidae) is a small invasive fly that is currently threatening Brassica vegetable and oilseed production in the Northeastern U.S. and Canada. Larvae feed on plant meristems, resulting in deformed leaves, stems, and heads. Extremely low damage thresholds for heading Brassica vegetables, multiple overlapping generations, and lack of effective organic insecticide options present serious challenges for managing this pest. Pheromone mating disruption (PMD), which involves confusing male insects with unnaturally large doses of sex pheromones, is particularly promising for swede midge management because it prevents mating and subsequent oviposition. One major challenge to PMD for swede midge management is that the chiral female pheromone blend, a 1:2:0.02 blend of (2S, 9S)-diacetoxyundecane, (2S, 10S)-diacetoxyundecane and (S)-2-acetoxyundecane, is expensive to synthesize due to the structural complexity of the compounds. Here, we explored three ways to reduce the cost of swede midge PMD: the use of lower-cost racemic pheromones containing all possible stereoisomers, single-component blends, and the possibility of using timed pheromone dispensers by testing for diel patterns of midge reproductive behavior. Although we found that males were not attracted to blends containing the racemic stereoisomers of the main pheromone component, (2S, 10S)-diacetoxyundecane, racemic blends functioned equally as well as chiral blends in confusing males and altering female behavior in PMD systems. We observed 95% and 87% reductions in males caught in monitoring traps in three-component chiral and racemic PMD plots of broccoli, respectively. In addition to confusing males, we also found that females altered their reproductive behavior in response to both chiral and racemic pheromones. Females released pheromones more frequently when exposed to three-component chiral and racemic blends, and were less likely to mate afterward. Single-pheromone treatments containing either chiral or racemic 2,10-diacetoxyundecane neither confused males nor influenced female behavior. We identified a total of eight hours during the day and night when midges do not exhibit mate-seeking behavior, during which programmable PMD dispensers could be turned off to save pheromone inputs. We found that up to 81% of females released pheromones to attract males for mating in the early morning shortly after dawn. Most females emerged in the morning as well, releasing pheromones soon after eclosing. Because midges are receptive to mates shortly after emergence, they may mate at their emergence site. Overall, we found relatively high levels of crop damage in our pheromone-treated plots, likely due to the migration of mated females into our plots. If midges mate at emergence sites, rotation of Brassica vegetable crops may result in overwintered midges emerging in fields where host plants are not currently grown. Further research is needed to determine where midges mate in order to determine where to install PMD dispensers.

A maioria dos Lepidoptera utiliza feromônio sexual para atração do parceiro para o acasalamento. A técnica da interrupção do acasalamento ou confusão sexual de machos é usada para interferir na comunicação entre os parceiros sexuais. Isto é obtido com a liberação de altas doses de feromônio sintético, para saturar o ambiente em que se deseja fazer o controle e, desta forma, diminuir a habilidade dos machos em localizar as fêmeas. O bicho-mineiro do café Leucoptera coffeella é considerado atualmente a principal praga desta cultura no Brasil. O controle químico tem sido o mais utilizado para impedir o ataque deste inseto, causando sérios problemas para o homem e para o meio ambiente. Para amenizar estes problemas, atualmente têm-se desenvolvido novas técnicas de manejo das pragas que atacam esta cultura. O presente trabalho testou, em campo, a viabilidade da técnica de confusão sexual de machos para a redução da população do bicho mineiro do café e com isso a diminuição do prejuízo que este inseto causa à lavoura. Foram instaladas três unidades experimentais de 20 ha. em uma lavoura de café. A eficiência desta técnica foi testada por meio da comparação de machos capturados em armadilhas iscadas com feromônio, entre a área tratada com o feromônio sexual para confundimento e outras duas áreas não tratadas com feromônio. Outra forma de avaliar a eficiência foi por meio da intensidade de injúrias que o inseto causou as folhas. Avaliando os resultados obtidos, pode-se implicar que o emprego do feromônio sexual sintético de L. coffeella não foi efetivo para reduzir os acasalamentos da espécie-praga e para diminuir o dano causado as plantas. Nesse contexto o insucesso pode ser atribuído a uma combinação de vários fatores, merecendo destaque à composição química, dose do feromônio e a formulação empregada, o momento de aplicação na lavoura, densidade populacional e a estratégia de acasalamento da praga, além do tamanho da área tratada e dos fatores climáticos._________________________________________________________________________________________ ABSTRACT: Most Lepidoptera use sex pheromones for the attraction of a mate. A technique for controlling lepidopteron pests, denominated mating disruption, aims at obstructing the communication between sexual partners. This is obtained with the release of synthetic pheromone in order to saturate the atmosphere, thereby decreasing the ability of mates to locate each other. The coffee leaf miner Leucoptera coffeella is the main pest of the coffee in Brazil. Chemical control has been used frequently to control the attack of L. coffeella, but this causes serious problems to man and environment. To avoid such problems, new techniques are being developed currently to control the attack of this pest. The present work is a field test of the viability of mating disruption to reduce coffee leaf miner populations and consequently, decrease its damage to the crop. Three experimental units of 20 ha. were installed in a coffee plantation. The intensity of mating disruption was tested through the comparison of synthetic-baited pheromone traps in areas where the sex pheromone was applied and two untreated areas. Another form to measure intensity of mating disruption was through the level of damage that the insect caused to the leaves. The results showed that the employment of the synthetic sex pheromone of L. coffeella did not reduce the mating of the insects and did not decrease the damage of plants. The failure of the mating disruption technique may be attributed to a combination of several factors, such as composition and/or dose of the pheromone and its formulation, the moment of application in the crop, the population density and the mating strategy of the pest, the size of the treated area as well as climatic factors.

Gravimetric analysis was used to determine the release rates and longevities of several designs of pheromone dispensers for mating disruption of leafrollers and codling moth, Cydia pomonella (Linneaus). Release rates were described by linear equations for at least four months, but by the end of the season release rates tended to become erratic. Biocontrol’s red-brown codling moth dispenser lasted for up to four months, and one application of the dispenser in early May should control codling moth for the entire season in Virginia apple orchards. Ecogen and Hercon leafroller dispensers lasted for a shorter time than the codling moth dispensers and would require two applications per season to provide the best control of their target pests. In a commercial northern Virginia apple orchard, the effects of pheromone trap height and pheromone dispenser height on captures of the tufted apple bud moth, Platynota idaeusalis (Walker), were studied. Low traps (2.0 m) were more sensitive than high traps (4.5 m) for monitoring tufted apple bud moth. The number of moths caught in 1994 and 1995 in a two-hectare mating disruption plot with pheromone dispensers placed in the upper third of the tree was not significantly different from the number caught in a plot with pheromone dispensers placed at head height. Fruit damage was very high in both pheromone plots in 1994, but by 1995 it appeared that mating disruption was able to reduce fruit damage due to leafroller larvae. / Master of Science

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv. / Härtill 6 uppsatser.

Made available in DSpace on 2015-03-26T13:30:46Z (GMT). No. of bitstreams: 1 texto completo.pdf: 315546 bytes, checksum: 7c3954ee8525d69ec5427b4b0a3dbabb (MD5) Previous issue date: 2006-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present thesis had the aim to study the importance of the host plant to the reproductive behavior of L. coffeella. At first, the following aspects were evaluated: (i) the effect of the reproductive condition of females in response to host plant volatiles; (ii) if mating proportion, initiation time and copulation duration are affected by the presence of volatiles in the host plant; (iii) and if females of L. coffeella, under no choice conditions, may be able to lay eggs in an alternative host. The efficiency of the mating disruption technique of males as a control method for this insect was also studied. In addition, the efficiency of PB-Rope dispensers was tested under low population conditions of adults in the field. These PB-Rope dispensers were used in order to saturate the environment with synthetic sexual pheromone and consist of a polyethylene tube containing 200 mg of 5,9-dimethylpentadecane, produced by Shin-Etsu Chemical Co. Ltd (Tokyo, Japan). In order to do so, the following hypotheses were tested: (i) that the PB-Rope dispenser provokes disorientation in males of L. coffeella in the areas treated with pheromone and (ii) that mating disruption leads to a decrease of lesions caused to the genus L. coffeella. In the first work, it was evidenced that only the volatiles emitted by the plant do not comprise relevant clue for females to spot their host. Nevertheless, they play an important role during the mating process. When another non-host plant was offered to the females as an oviposition site, it was observed that there was a considerable reduction in the number of laid eggs, indicating that females use cues of the host plant for oviposition. In the second work, the number of males captured in the pheromone traps in the treated area was reduced in relation to the control areas; however, the damage that this insect causes to the plantation was not different between the treated areas and the control areas. In this case, it was not possible to quantify the efficiency of the technique because the same levels of mined leaves and eggs were found in both areas. / Nesta tese foi estudada a importância da planta hospedeira no comportamento reprodutivo de L. coffeella. Inicialmente avaliou-se: (i) o efeito da condição reprodutiva das fêmeas em resposta aos voláteis da planta hospedeira; (ii) se a proporção de acasalamento, tempo de início e duração da cópula são afetadas pela presença de voláteis da planta hospedeira; (iii) e se fêmeas de L. coffeella, em condições de não escolha, podem ovipositar em hospedeiro alternativo. Foi estudada também a eficiência da técnica de confusão sexual de machos como método de controle deste inseto. Foi testada a eficiência dos liberadores de feromônio PB-Rope em condições de baixa população de adultos em campo. Estes liberadores PB-Rope foram usados para saturar o ambiente com feromônio sexual sintético e consistem de um tubo afilado de polietileno contendo 200 mg de 5,9-dimetilpentadecano, fabricados pela Shin-Etsu Chemical Co. Ltda (Tókio, Japão). Para isto testaram-se as hipóteses: (i) de que nas áreas tratadas com feromônio, o liberador PBRope provoca desorientação nos machos de L. coffeella e (ii) que a confusão sexual leva a redução das injúrias causadas ao cafeeiro por L. coffeella. No primeiro trabalho, ficou evidenciado que os voláteis sozinhos emitidos pela planta não constituem pista relevante para as fêmeas localizarem seu hospedeiro, porém têm papel importante durante o acasalamento. Quando ofereceu-se às fêmeas outra planta não hospedeira como sítio de oviposição, pode-se observar uma redução considerável no número de ovos depositados, indicando que as fêmeas usam pistas da planta hospedeira para a oviposição. No segundo trabalho, o número de machos capturados nas armadilhas de feromônio nas áreas tratadas foi reduzido em relação às áreas controles, mas, o dano deste inseto à lavoura não foi diferente entre as áreas tratadas e áreas controles. Neste caso, não foi possível quantificar a eficiência da técnica porque os mesmos níveis de folhas minadas e ovos foram encontrados em ambas as áreas.

California red scale (CRS), Aonidella aurantii, is an increasingly injurious insect pest for the California citrus industry due to insecticide resistance, changing weather patterns, and shifting trade regulations. The presence of the insect on fruit, damages the rind of the fruit and high populations can cause dieback of branches as well as lower yields. Pheromone mating disruption of CRS has the potential to alleviate population control concerns and reduce insecticide use. The efficacy of the pheromone mating disruption technique for pest management of CRS was determined using the products CheckMate® CRS and Semios CRS Plus. CheckMate® CRS was evaluated over two years in eight 8.1-ha blocks and two 16.2-ha blocks, and in each block half the acreage was untreated and half treated. Semios CRS Plus was evaluated over one year in four 8.1-ha blocks and one 16.2-ha block, and in each block half the acreage was untreated and half treated. Disruption efficacy was determined by male flight trap counts, leaf and twig infestation percentages, and fruit infestation at the end of the season. For CheckMate® CRS® a large reduction in male flight trap catches were recorded in all blocks over both years. Statistically significant lower leaf and twig infestations were observed between for the CheckMate® CRS compared to the control areas in all 10 blocks over the 2018 and 2019 seasons for both the August and November sampling. Statistically significant reductions in the % of fruit infested with 10 or more scales were observed for the CheckMate® CRS treatment compared to the control in 9 of the 10 blocks with 7 of 10 blocks having 90% to 97% reduction. No significant reductions in male flight trap catches or the August leaf and twig infestation were observed for Semios CRS Plus. Due to a lack of efficacy in the August leaf and twig sample in 2018 the trials were canceled and not replicated in 2019. The results of the study indicated pheromone mating disruption using CheckMate® CRS, can be an effective method to reduce California red scale populations.