Search Results

You are looking at 91 - 100 of 455 items for :

  • "insect pests" x
Clear All
Free access

Megan Ulmer, Regina Ali, Conrad Bonsi, Louis Jackai and Bryon Sosinski

The sweetpotato weevil (SPW), Cylas formicarius, is the most devastating insect pest of sweetpotato worldwide. In the U.S., the devastation by this pest costs the sweetpotato industry several million dollars in crop loss and lost income each year. Many growers in highly infested areas have simply abandoned growing sweetpotatoes. The overall project goals are to elucidate the routes used for the spread of the SPW, and to determine the existence of intra-specific variation in the SPW population in the US and selected overseas countries. These results will lead to more effective and targeted management of the SPW. Results will also make quarantine enforcement more efficient. We are examining the highly conserved and phenotypically neutral rDNA sequences of both the 18S and ITS1 regions of the SPW genome as a way to determine the population structures and origins of SPW in the US. Here, the molecular genetic aspects of the project are outlined, and preliminary results are presented.

Free access

Raúl Leonel Grijalva-Contreras, Arturo López-Carbajal, Adán Fimbres-Fontes, Cristobal Navarro-Ainza, Rogelio Juárez-González and Fabián Robles-Contreras

Apricot production in México is limited; actually, the area devoted to this crop is ≈880 ha, from which 230 ha are established in Sonora State. The main cultivar is `Canino'. The fruit yield ranges from 15 top 20 t·ha-1. The present study tested 20 low-chilling (300-400 chill hours) requirements of apricot selections; `Nemaguard' was the rootstock used. On the fourth production year, from the 20 apricot selections tested, 7-23, 1-81, and 15-1 yielded 31.8, 20.2, and 15.5 t·ha-1, respectively. all of these selections showed higher yields than `Canino' (14.6 t·ha-1). The fruit of these apricot selections ripened by mid-May, exhibiting a similar fruit quality (size, flavor, color, and °Brix) in all the tested selections. We have not recorded any important insect pests or diseases during this trial.

Free access

Raúl Leonel Grijalva-Contreras, Arturo López-Carbajal, Adán Fimbres-Fontes, Cristobal Navarro-Ainza, Rogelio Juárez-González and Fabián Robles-Contreras

Apricot production in México is limited; actually, the area devoted to this crop is ≈880 ha, of which 230 ha are established in Sonora State. The main cultivar used is `Canino'. The fruit yield ranges from 15-20 t·ha-1. The present study tested 20 low-chilling (300 to 400 chill hours) requirments of apricot selections; `Nemaguard' was the rootstock used. On the 4rth production year from the 20 apricot selection tested, 7-23, 1-81, and 15-1 yielded 31.8, 20.2. and 15.5 Ton.Ha-1, respectively; all of these selections showed higher yields than the Canino cultivar (14.6 t·ha-1). The fruit of these apricot selectiosn ripened by mid-May, exhibiting all the tested selection a similar fruit quality (size, flavor, color, and °Brix). We have not recorded any important insect pests or diseases during this trial.

Free access

Shahrokh Khanizadeh and Jamshid Ghavami

UniBase is a Windows-based (95, 98, NT, 2000, or XP) user-friendly software package that was developed for those who are interested in creating their own instant databases, add information to an existing databases or import data and images from Excel in a choice of languages. The software is very useful for germplasm inventory (fruit crops, vegetables, ornamentals, agronomic crops, weeds, chemicals, insects, pests, animals, etc.) and can be used in any breeding program (animal, horticulture, agronomy, etc.) to trace pedigrees and view images and characteristics of progenies. The database can be searched using various criteria and the use of several operators. An unlimited number of images can be stored for each entry and several graphic formats including BMP, JPEG, GIF, TIFF, etc., can be used. Additional information on UniBase and available data and images can be obtained from the authors.

Free access

Michael W. Smith

Several new management tools and management practices are being developed for pecan. Major insect pests of pecan are pecan nut casebearer, hickory shuckworm, and pecan weevil. Sex pheromone attractants are being developed for each of these pests that improve monitoring. Also, a pecan weevil trap (Tedder's trap) was introduced recently that is more sensitive to weevil emergence than the previous trap. New models that predict critical periods for pecan scab infection are being tested. Certain legume ground covers are being tested to increase beneficial arthropods in the orchard for aphid control, and to supply N. Mulches are being investigated as an alternative to herbicide management for young trees. A mechanical fruit thinning method has been developed that increases fruit quality and reduces alternate bearing as well as stress-related disorders.

Free access

Arlette S. Cuomo, Steven E. Newman, Hassan H. Nassar and Ronald J. Harkrader

There are many naturally occurring substances that have the potential to be adapted to modern pest control chemistry. Azadirachtin, an insect growth regulator, is one such naturally occurring compound that has been widely accepted in insect pest management. Quartenary benzophenanthridine alkaloids (QBAs) are known to be effective in the control of crop-damaging fungal diseases. QBAs can be isolated from plants in the Papaveraceae. Extracts of Macleaya cordata, a species rich in QBAs, were formulated for drench application to Cucumis sativa `White Wonder' seedlings. The seedlings were grown in a peat-lite medium using 10-cm plastic pots and inoculated with Rhizoctonia solani. Test formulations were prepared with and without QBAs and applied at 75, 150, and 300 ppm QBAs as a 100 ml/pot drench. The QBA formulations that provided effective control of Rhizoctonia solani lost 20% or fewer seedlings compared to the formulation without QBA, which lost more than 60% of the seedlings. Treated plants were evaluated confirming Rhizoctonia solani infection.

Free access

Louise Ferguson, Harry Shorey and David L. Wood

Several experimental procedures were used to evaluate the influence of solar radiation on insect infestations in Calimyma and Adriatic variety figs (Ficus carica L.). Direct sunlight eliminated infesting insects and prevented further infestation of ripe figs drying on the ground for at least 10 days. Placement in the shade resulted in 12% insect infestation in figs within 3 days. Figs that fell naturally into sunlit areas contained almost no insects, whereas 31% of figs that fell into dense shade were infested. While ripening figs were still attached to trees, the level of insect infestation was 50% higher on the shady north side than the sunny south south side. The insect pests most frequently encountered in these experiments were nitidulid beetles and their larvae. Disease incidence was not affected by degree of exposure. We propose that cultural techniques to maximize exposure of ripening and drying figs to solar radiation could be developed as important pest management tools.

Free access

Shelley Jansky, Sandra Austin-Phillips and Corine McCarthy

The Colorado potato beetle (CPB) is a major insect pest that is controlled mainly through the use of pesticides. Development of potato clones with multiple forms of host plant resistance may provide a stable alternative or supplemental form of CPB control. Tetraploid hybrids were developed by somatic fusion of diploid interspecific Solanum clones with different forms of resistance to CPB. Hybrids were created between a clone containing leptine glycoalkaloids and four clones producing glandular trichomes. One fusion produced vigorous hybrids that were analyzed for CPB resistance traits. Somaclonal variation among hybrids was detected for trichome density and resistance to feeding by adult and larval beetles. Somatic hybrids were less resistant than the parents in adult feeding preference trials, but several were more resistant than either parent in larval feeding trials. Future studies are needed to determine whether clones producing both glandular trichomes and leptines express resistance that is more stable than that of clones with only one resistance factor.

Full access

Harry Bottenberg, John Masiunas, Catherine Eastman and Darin Eastburn

Field studies were conducted to determine insect and plant pathogen management effects on weed competitiveness and crop yield and to evaluate weed management impacts on insect pests, diseases, and crop yield. At similar densities, redroot pigweed (Amaranthus retroflexus L.) reduced snapbean (Phaseolus vulgaris L.) and cabbage (Brassica oleracea L. var capitata) yield more than that of common purslane (Portulaca oleracea L.), a low growing weed. In 1995, diamondback moth [Plutella xylostella (L.)] was greater on cabbage growing in plots with purslane than in plots of cabbage growing without weeds. Imported cabbageworm [Pieris rapae (L.)] was greater on cabbage growing in plots with either purslane or pigweed than when growing alone. However, the amount of feeding damage to cabbage was similar across treatments. Disease incidence was low, but fungicide treatments made redroot pigweed more competitive with snapbean, reducing yield in 1995.

Free access

Rosalía Servín, Jos L. Martínez, E. Troyo-Diguez and A. Ortega

The sweetpotato whitefly [Bemisia tabaci (Gennadius)] has become a high-risk insect pest in Mexico as well as in other countries, causing serious damage to several crops. Control of whitefly in Baja California Sur, ,Mexico, is usually done by intense insecticides applications, either alone or in mixtures of several kinds. The aim in this work was to determine its susceptibility to cypermethrin, endosulfan, methamidophos, and methyl-parathion. LC50 was obtained to identify the resistant and susceptible populations. A group of 20 whiteflies were introduced in a 20-ml scintillation vial coated in the inner surface with a known concentration of the insecticide. Mortality readings were obtained 3 h after exposing the insects to the residual activity at five concentrations. Five replications and control were run in different consecutive days for each bioassay. Results indicated that cypermethrin was the most toxic to B. tabaci and metamidophos the least. Data will be considered for further evaluations.