Application of entomopathogenic fungi by inundative releases has been attempted for control of a wide range of insect pests, with generally poor results. This is largely because entomopathogens are often treated as direct substitutes for chemical insecticides and applied without an adequate knowledge of their interactions with the local environment. Humidity of greater than 90% RH has long been regarded as the a critical condition for germination and infection by the spores. With both temperature and humidity controlled, greenhouse crops offer an excellent potential for pest control using entomopathogens. The long-term maintenance of >90% RH, however, is not standard practice in greenhouse production. This study explored the possibility of improving the efficacy of the fungi by temporarily changing greenhouse humidity without adversely affecting crop growth. The study included laboratory and greenhouse trials. In laboratory trials, four humidity levels of 75%, 80%, 89%, and 97.5% RH were evaluated over a 48-h period. Three commercial products of Beauveria bassiana were evaluated (Naturalis-O, Botanigard 22 WP, and Botanigard ES). Greenhouse pests of green peach aphid, melon aphid, western flower thrips, whitefly, and two-spotted spider mite were used as target insects. The infection rate of B. bassiana was found to increase when the sprayed adult insects were exposed to higher humidity levels with the maximum infection obtained at 97.5% RH. Percent infection and difference between humidity levels, however, were formulation- and host-dependent. The highest overall control efficacy was obtained by using Botanigard ES. Botanigard ES was highly effective to adult green peach aphid, melon aphid, and greenhouse whitefly at high humidities. Effects of B. bassiana against biological control agents for greenhouse vegetable crops were also evaluated. Greenhouse trials were conducted in two adjacent greenhouse compartment with high and low humidity conditions for 48 h, respectively, for selected pest insects to valid laboratory results.
Fredric Miller and Susan Uetz
Horticultural oil and insecticidal soap were as effective as conventional insecticides and miticides in controlling a variety of sap-feeding insects and mites on common greenhouse crops. Neem extract (Margosan-O or Azatin) was less consistent and provided intermediate to good control of a variety of sap-feeding insects and mites on common greenhouse crops. Except for purple heart (Setcreasea purpurea K. Schum. & Sydow) and wax ivy (Hoya carnosa R. Br.), repetitive sprays of horticultural oil, insecticidal soap, and neem extract (Azatin) did not seem to cause any noticeable phytotoxicity or effect the growth of 52 species or cultivars of bedding plants and 13 species of foliage plants examined in this study. Repetitive sprays of horticultural oil and insecticidal soap significantly affected plant height and final quality of some poinsettia cultivars evaluated in this study.
Y. Zhang, J.L. Shipp, and T.J. Jewett
Overhead fogging or misting is an essential technique applied in modern greenhouses for cooling and humidifying. This technique can be used to promote yield and quality of greenhouse crops either by providing favorable environment for the plant growth or by increasing the efficiency of greenhouse pest and disease control. In this study, the effect of high-pressure overhead misting on greenhouse climate and leaf surface microclimate conditions for cucumber crops in a glass greenhouse was investigated. It was found that the temperature of the greenhouse air was lowered by 5-6 °C and relative humidity was increased by 20% to 30% during misting. The temperature of sunlit leaves was slightly reduced in the morning (2-3 °C), and leaf wetness duration was significantly extended by misting. Leaf wetness duration under misting was predominately influenced by light intensity at the leaf level and was modelled as a function of misting period and average radiation intensity. Results of this study can be used to improve the predictions of pest and disease breakout and the efficiency of their control measures. The empirical model developed in this study can be integrated with leaf surface microclimate models to correctly predict surface moisture conditions and evaporative cooling from water films at the leaf surface.
J.D. Willmott and R.N. Freeman
Rutgers Cooperative Extension and Cornell Cooperative Extension initiated a regional newsletter the Northeast Greenhouse IPM Notes. The goal of the newsletter is to improve greenhouse pest management practices through promotion of timely integrated pest management information that applies to the unique problems faced in the Northeastern United States. Interstate cooperation maximizes the professional expertise and resources available through several Land Grant Institutions. Extension educators at Cornell, Rutgers, Penn State Univ., and the Universities of Maryland and Connecticut, actively contribute feature articles, pest updates and other timely information through e-mail: Internet communication facilitates communication. The newsletter is prepared monthly and sent to 282 greenhouse growers, extension professionals and allied industry representatives in New Jersey, New York, Pennsylvania, Connecticut, Massachusetts, and other states. The newsletter is also published on the World Wide Web with color images of crop problems. Publishing of color images is facilitated by digital technology. This edition can be downloaded in color from the Rutgers Cooperative Extension Floriculture site: http://aesop.rutgers.edu/~floriculture/grower/ipmf.htm
Charles L. Rohwer and John E. Erwin
Jasmonates are a class of plant hormones involved in plant defense and stress responses. For example, jasmonate-induced defense responses in Lycopersicon esculentum include increases in activity of proteinase inhibitors, polyphenol oxidases, and peroxidases. As part of our efforts to reduce or control greenhouse pest infestations, we hypothesized that methyl jasmonate (MeJA) could induce these biochemical changes in common greenhouse crops. We studied Impatiens wallerana `Super Elfin Pink', L. esculentum `Big Boy', Petunia ×hybrida `Bravo Lavendar', Viola ×wittrockiana `Imperial Beaconsfield', Coleus ×hybridus `Wizard Jade', Nicotiana alata `Saratoga Lime', Pelargonium ×hortorum `Pinto Pink', and Tagetes erecta `Antigua Primrose'. Polyphenol oxidase and peroxidase activity was studied in the first four species, and proteinase inhibitors were studied in all eight. We sprayed plants with 0, 5 × 10-6, or 10-4 molar MeJA and made measurements after 24 hours. We detected a small increase in polyphenol oxidase activity of plants treated with 10-4 molar MeJA; 5 × 10-6 molar had no effect, and L. esculentum had the highest polyphenol oxidase activity. Peroxidase activity was not affected by MeJA. I. wallerana had the highest peroxidase activity, L. esculentum and V. ×wittrockiana had the lowest. 5 × 10-6 molar MeJA increased proteinase inhibitor activity in most species, and 10-4 molar increased activity in every species except P. ×hortorum.
Kent D. Kobayashi
, several broad search terms such as horticulture, agriculture, soil, greenhouse, pests, and irrigation can be used. Apps that meet a search criterion will be displayed. For example, a search done in Feb. 2013 on “horticulture” resulted in 26 search results
Christopher J. Currey and Roberto G. Lopez
9813-6N; Hanna Instruments, Woonsocket, RI). Greenhouse pests were monitored with sticky cards and plant inspections ( Gill and Sanderson, 1998 ; Powell and Lindquist, 1997 ). Yellow sticky cards were placed among the poinsettias at canopy height and
Laura Pickett Pottorff and Karen L. Panter
nonpesticidal method for controlling diseases, nematodes, and weeds Univ. California Div. Agr. Natural Resources Publ. 21377 Gill, S. Sanderson, J. 1998 Ball identification guide to greenhouse pests and beneficials Ball Publishing Batavia, IL Greer, L. Diver, S
Erick X. Caamano, Raymond A. Cloyd, Leellen F. Solter, and Declan J. Fallon
, K. 1998 Evaluation of the quality of four commercially available natural enemies Biol. Control 11 1 8 Parrella, M.P. Heinz, K.M. 1998 Parasitoids for control of greenhouse pests 27 39 Ridgeway R. Hoffman M. Insoe M. Glenister C. Mass-reared natural
Alan Petravich, James F. Harbage, and Matthew Taylor
excessive heat in the greenhouses. Pests and Hazards At Longwood Gardens, insect pests include mealy bugs, thrips, snails, and slugs. Clivia cannot tolerate direct noon day sun, and need protection from intense sunlight; otherwise leaves will quickly