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Detecting water quality improvements following watershed management changes is complicated by flow‐dependent concentrations and nonlinear or threshold responses that are difficult to detect with traditional statistical techniques. In this study, we evaluated the long‐term trends (1997–2009) in total P (TP) concentrations in the Illinois River of Oklahoma, and some of its major tributaries, using flow‐adjusted TP concentrations and regression tree analysis to identify specific calendar dates in which change points in P trends may have occurred. Phosphorus concentrations at all locations were strongly correlated with stream flow. Flow‐adjusted TP concentrations increased at all study locations in the late 1990s, but this trend was related to a change in monitoring practices where storm flow samples were specifically targeted after 1998. Flow‐adjusted TP concentrations decreased in the two Illinois River sites after 2003. This change coincided with a significant decrease in effluent TP concentrations originating with one of the largest municipal wastewater treatment facilities in the basin. Conversely, flow‐adjusted TP concentrations in one tributary increased, but this stream received treated effluent from a wastewater facility where effluent TP did not decrease significantly over the study period. Results of this study demonstrate how long‐term trends in stream TP concentrations are difficult to quantify without consistent long‐term monitoring strategies and how flow adjustment is likely mandatory for examining these trends. Furthermore, the study demonstrates how detecting changes in long‐term water quality data sets requires statistical methods capable of identifying change point and nonlinear responses.

Lake Allatoona is a large reservoir northeast of metropolitan Atlanta, GA, threatened by excessive algal growth. We used the calibrated Soil and Water Assessment Tool (SWAT) models developed in our companion paper to estimate the annual P load to Lake Allatoona in 1992 and in 2001 after significant changes occurred in land use. Land use data in 1992 and 2001 from the Multi‐Resolution Land Characteristics (MRLC) Consortium showed that forest land use decreased during this period by about 20%, urban land use increased by about 225%, and pasture land uses increased by about 50%. Simulation results showed that the P load to Lake Allatoona increased from 176.5 to 207.3 Mg, which were 87.8% and 103.1%, respectively, of the total P (TP) annual cap (201 Mg) set by the Georgia Environmental Protection Division (GAEPD) for discharge into Lake Allatoona. In the early 1990s, the greatest sources of the TP load to Lake Allatoona (and their percentages of the total load) were pasture (33.6%), forest (27.5%), and point sources (25.0%). Urban land uses contributed about 6.0% and row‐crop agriculture contributed about 6.8%. A decade later, the greatest two TP sources were pasture (52.7%) and urban (20.9%) land uses. Point‐source P loads decreased significantly to 11.6%. Permit limits on poultry processing plants reduced the point‐source P loads, but increasing urban and pasture land uses increased nonpoint sources of P. To achieve further reductions in the P load to Lake Allatoona, contributions from pasture and urban nonpoint sources will need to be addressed.

Lake Allatoona is a large reservoir north of Atlanta, GA, that drains an area of about 2870 km2scheduled for a phosphorus (P) total maximum daily load (TMDL). The Soil and Water Assessment Tool (SWAT) model has been widely used for watershed‐scale modeling of P, but there is little guidance on how to estimate P‐related parameters, especially those related to in‐stream P processes. In this paper, methods are demonstrated to individuallyestimate SWAT soil‐related P parameters and to collectivelyestimate P parameters related to stream processes. Stream related parameters were obtained using the nutrient uptake length concept. In a manner similar to experiments conducted by stream ecologists, a small point source is simulated in a headwater sub‐basin of the SWAT models, then the in‐stream parameter values are adjusted collectivelyto get an uptake length of P similar to the values measured in the streams in the region. After adjusting the in‐stream parameters, the P uptake length estimated in the simulations ranged from 53 to 149 km compared to uptake lengths measured by ecologists in the region of 11 to 85 km. Once the a priori P‐related parameter set was developed, the SWAT models of main tributaries to Lake Allatoona were calibrated for daily transport. Models using SWAT P parameters derived from the methods in this paper outperformed models using default parameter values when predicting total P (TP) concentrations in streams during storm events and TP annual loads to Lake Allatoona.

According to EU Directive 2001/18/EC, a general surveillance monitoring must be implemented to detect possible unexpected effects of genetically modified (GM) crops on the environment. Butterflies have been proposed to be suitable indicators for monitoring environmental changes in agricultural landscapes. Using such mobile organisms as indicators for general surveillance is a challenge as their populations vary according to many environmental factors acting at the field, landscape and regional scales. They might thus not be appropriate to detect unexpected effects of GM crops, unless the sources of variation in their populations can be identified and accounted for. In the present study we use a multiscale approach to describe the interactions between butterfly populations, the environment and farming activities. We analysed existing butterfly data from several Swiss agricultural landscapes in order to identify the sources of variation in butterfly populations and to give guidelines for the design of general surveillance protocols for butterflies.

Abstract: A major concern regarding the deployment of insect resistant transgenic plants is their potential impact on non-target organisms, in particular on beneficial arthropods such as predators. To assess the risks that transgenic plants pose to predators, various experimental testing systems can be used. When using tritrophic studies, it is important to verify the actual exposure of the predator, i.e., the presence of biologically active toxin in the herbivorous arthropod (prey). We therefore investigated the uptake of Cry1Ab toxin by larvae of the green lacewing (Chrysoperla carnea (Stephens); Neuroptera: Chrysopidae) after consuming two Bt maize-fed herbivores (Tetranychus urticae Koch; Acarina: Tetranychidae and Spodoptera littoralis (Boisduval); Lepidoptera: Noctuidae) by means of an immunological test (ELISA) and the activity of the Cry1Ab toxin following ingestion by the herbivores. Moreover, we compared the activity of Cry1Ab toxin produced by Bt maize to that of purified toxin obtained from transformed Escherichia coli, which is recommended to be used in toxicity studies. The activity of the toxin was assessed by performing feeding bioassays with larvae of the European corn borer (Ostrinia nubilalis (Hübner); Lepidoptera: Crambidae), the target pest of Cry1Ab expressing maize. ELISA confirmed the ingestion of Bt toxin by C. carnea larvae when fed with either of the two prey species and feeding bioassays using the target pest showed that the biological activity of the Cry1Ab toxin is maintained after ingestion by both herbivore species. These findings are discussed in the context of previous risk assessment studies with C. carnea. The purified Cry1Ab protein was more toxic to O. nubilalis compared to the plant-derived Cry1Ab toxin when applied at equal concentrations according to ELISA measurements. Possible reasons for these findings are discussed.

Trichogrammaspp. (Hymenoptera: Trichogrammatidae) only rarely parasitize eggs of Helicoverpa armigera(Hübner) (Lepidoptera: Noctuidae) on pigeonpea (Cajanus cajan(L.) Millspaugh), while on other plants including sorghum (Sorghum bicolor(L.)) high parasitism levels of this host are found. In this study two strategies designed to increase the parasitoid activity on pigeonpea were tested in the field: intercropping pigeonpea with sorghum and mass‐releasing T. chilonisIshii. Neither strategy led to an increase in parasitism. On pigeonpea, H. armigeraoviposited >74.8% of its eggs on calyxes and pods. Parasitism levels in host eggs collected from different plant structures varied significantly with 3.6, 0.3, and 40.7% of eggs on calyxes, pods, and leaves parasitized. Earlier studies have shown that calyxes and pods possess long glandular and non‐glandular trichomes, and are covered by sticky trichome exudates which inhibit parasitoid searching behaviour. Parasitism levels between 27.9 and 100% were recorded from host eggs on the intercropped sorghum. Trichogramma chilonis was the dominant parasitoid species. The mean clutch size was 2.03, but up to six parasitoids emerged per egg. Progeny sex ratio (% females) decreased with clutch size, from 63.1% at a clutch size of one to 46.0% at a clutch size of five. Sticky trap catches showed that while the parasitoid population in sorghum increased when H. armigerastarted ovipositing, the population within pigeonpea did not benefit from either a high parasitoid population in sorghum or a high host egg density on pigeonpea. During one of five seasons studied, however, high parasitism levels (up to 73%) were recorded on pigeonpea. During this season, H. armigeraoviposited on pigeonpea plants in the vegetative growth stage and a high proportion of eggs were collected from leaves. Parasitism levels were positively correlated with the percentage of eggs collected from leaves. This study shows that the parasitization efficiency of Trichogramma spp. on pigeonpea depends mainly on the location of the host eggs. This explains why parasitism levels of H. armigeraeggs on pigeonpea did not increase when intercropped with sorghum or after mass‐releasing T. chilonis.

Trichomes have been modified in a number of crops to develop insect‐tolerant genotypes. Pigeonpea, Cajanus cajan(L.) Millsp., is often heavily damaged by insect pests, and trichomes provide a potential insect resistance mechanism. The following study was conducted to identify and characterize the distribution of trichomes on pigeonpea and two wild species, C. platycarpus(Bentham) van der Maesen and C. scarabueoides(L.) Thours. Three glandular (Types A, B, and E) and two nonglandular (Types C and D) trichome types were identified with light and electron microscopy. Types A, B, C, and D were found on leaves, pods, and calyxes of all three Cajanusspp., except for Type A, which was not found on pods and calyxes of most C. scarabaeoidesaccessions examined. Because of their small size and rarity, Type E trichomes were not considered in this study. Pods of C. scarabueoideswere the most densely pubescent, followed by pods of C. cajanand C. platycarpus. Trichome density on pods varied significantly among pigeonpea genotypes and different accessions of C. scarabaeoides. Differences across seasons and in greenhouse versus field‐grown plants were also significant. Leaves of C. platycarpuspossessed the fewest trichomes, while C. cajanand C. scarabaeoideshad highly pubescent leaves. The resistance of C. scarabaeoidespods to Helicoverpa armigera(Hübner) larvae reported in an earlier study is due to the high density of nonglandular trichomes. This wild species may thus be an important source for developing insect resistant pigeonpea.

The habitat‐ and host‐searching behaviour of female Encarsia formosaGahan (Hymenoptera: Aphelinidae) was assessed using an airflow olfactometer and a filter paper test. Responses to different odour cues, colours, host‐produced honeydew, non‐host honeydew and single carbohydrates were determined. The parasitoid was not attracted to or arrested by odours emanating from clean tobacco leaves, tobacco leaves heavily infested with the host Trialeurodes vaporariorum(Westwood) (Homoptera: Aleyrodidae) and covered with honeydew, or honeydew alone. However, E. formosafemales showed a significant response to green light transmitted through a tobacco leaf. The yellow part of the spectrum was partly responsible for this response. Thus, the long‐range orientation is random with respect to the presence of hosts. Filter paper tests showed that the short‐range searching behaviour is influenced by water soluble, non‐volatile contact‐kairomones contained in the host‐produced honeydew. Contact with honeydew excreted by L3/L4 T. vaporariorumresulted in longer searching times than honeydew from adult T. vaporariorumor L3/L4 Bemisia tabaciGennadius (Homoptera: Aleyrodidae). No difference was found between the response to honeydew excreted by adult and L3/L4 B. tabaci. The parasitoids' response to honeydew was unaffected by the host plant on which the whiteflies had fed. Non‐host honeydew and single carbohydrates also affected the searching behaviour of E. formosabut to a lower extent than host honeydew. The possible differences in the carbohydrate and amino acid composition of the honeydew excreted by different life‐stages of T. vaporariorumand B. tabaciare discussed.

The response of Trichogramma spp. egg parasitoids to colored sticky traps was evaluated in the field during two seasons (1995/1996, 1996/1997). Traps consisted of a glass tube coated with Bird-Tanglefoot® into which colored paper was inserted or clear traps without paper. Colors tested were white, green, blue, yellow and red in the first season and white, green, yellow and black in the second season. The proportion of both female and male parasitoids caught on the sticky traps was significantly different among colors, indicating that the parasitoids actively move between plants and are not solely carried along passively by wind. White was the color most preferred by female parasitoids, followed by clear and green traps. Yellow was preferred over black but was less attractive than green. Visual cues may be used by Trichogramma spp. during the habitat location process. The color preference of male Trichogramma spp. differed significantly from females with yellow and green being more attractive than white. For all colors, more female Trichogramma spp. were caught on the sticky traps (>85% of all wasps caught), indicating a lower activity level and/or shorter lifespan for males. The use of white cylindrical sticky traps for monitoring Trichogramma spp. populations in the field is recommended.

The use of Trichogramma (Hymenoptera: Trichogrammatidae) egg parasitoids for the biological control of several insect pests, including the pod borer Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), is being promoted in India. Several companies supply these parasitoids to farmers, but no evaluation of product quality has been made. Low product quality is recognized as being one of the most important reasons for the failure of these biocontrol agents. In this study, Trichogramma chilonis Ishii egg-cards were obtained from eight producers in southern India. Product quality was evaluated using the following parameters: number of eggs/card, percentage parasitism, percentage emergence, progeny sex ratio and percentage of deformed females. In addition, producers were asked for the average values of these parameters in their production systems and for their recommendations for the use of T. chilonis to control H. armigera in cotton. The quality of the egg-cards was highly variable and was much lower than that stated by the producers. The recommended frequency and interval of releases, and the number of parasitoids to be released, differed greatly among producers. The low product quality results in up to 85% fewer parasitoids being released than is recommended by the producer. The effect of the low product quality and the highly variable release recommendations on applied biological control programmes is discussed. Suggestions for more effective use of Trichogramma spp. are given.

Helicoverpa armigera Hubner Lepidoptera: Noctuidae is one of the most serious insect pests in the Old World. In India, it causes substantial losses to legume, fibre, cereal oilseed and vegetable crops. This paper reviews the literature on the biology, ecology, efficacy, rearing and augmentation of endemic parasitoids and predators, as well as exotic parasitoids introduced and released in India. It also provides updated lists of H. armigera natural enemies native to India. In addition, reports of augmentative releases of Trichogramma spp., the most extensively studied natural enemy of H. armigera are summarized.

Several plant characters are known to affect the searching behaviour and parasitization efficiency of Trichogrammaspp. (Hymenoptera: Trichogrammatidae). In this study, plant characters contributing to the low Helicoverpa armigera(Hübner) (Lepidoptera: Noctuidae) egg parasitism levels on pigeonpea (Cajanus cajan(L.) Millspaugh) were investigated. The efficiency of T. chilonison pigeonpea was dependent on the plant structure on which the host eggs were found. In a cage experiment, more than 55% of eggs placed on leaves were parasitized, while 1% of eggs on calyxes and no eggs on pods were parasitized. In a filter paper bioassay, parasitoids were deterred by acetone and hexane surface extracts from pigeonpea pods but showed no response to water extract. The searching behaviour of the parasitoids was not affected by different solvent extracts from the surface of pigeonpea leaves. In a four‐armed airflow olfactometer, T. chiloniswas repelled by volatiles from pigeonpea pods but showed no response to volatiles derived from hexane extract of pod surfaces. Volatile infochemicals and hexane surface extracts from pods of two wild Cajanusspecies, C. scarabaeoides(L.) Thours and C. platycarpus(Bentham) van der Maesen, were similarly deterrent to T. chilonis. The movement of the parasitoids on pigeonpea pods and calyxes was inhibited by long trichomes and wasps were trapped by sticky trichome exudates. Parasitoids walked significantly faster on leaves than on pods. The walking speed on both pods and leaves increased significantly after washing with hexane. The results presented in this paper show that the plant growth stage and the plant structures preferred by H. armigerafor oviposition are the least suitable for T. chilonis, contributing to the low parasitoid efficiency on pigeonpea.