Production of sweetpotatoes is severely limited by several insect pests, and new pest management approaches for this crop are needed. A host plant resistance research program typically depends on reliable bioassay procedures to streamline evaluation of germplasm. Thus, bioassay procedures were developed for both adults and larvae of two cucumber beetle species (Diabrotica balteata and D. undecimpunctata). For the adult bioassay, a piece of sweetpotato peel (periderm & cortex with stele removed) was embedded periderm-side up in plaster in a Petri dish, and a single adult was placed on it. Plugs were changed as needed and adult longevity was measured. A laboratory bioassay also was developed for Diabrotica larvae. Plugs (0.9 cm diameter) of sweetpotato peel or stele were placed periderm-side up into sterile microcentrifuge tubes (1.5 mL) containing 0.5 mL water-agar to prevent desiccation. One second instar Diabrotica was added to each micro centrifuge tube, which was held at 25 °C for 12 days. Surviving larvae were weighed. Diabrotica larvae grew larger when they were fed stele than when they were fed peels of any sweetpotato genotype. Larval growth was not different among genotypes for any of the stele treatments. However, larval growth on the peel of the resistant genotypes (Regal and W-375) was significantly lower than for the susceptible cultivars Beauregard or SC1149-19. These bioassays were consistent with field results, indicating that these techniques could be useful for evaluating pest resistance in sweetpotato genotypes for Diabrotica and other insect species.
Abstract
In the early 1970s, a study was begun to find resistance to feeding in muskmelon, Cucumis melo L., by banded cucumber beetles, Diabrotica balteata LeConte. Bitter seedlings were observed to be more susceptible to feeding than nonbitter seedlings. We noticed reduced damage levels in both bitter and nonbitter seedlings in 1974. Genetic study of resistant materials showed that in addition to the recessive form of the bitter gene, bibi, a 2nd recessive gene, cbl cbl, conditioned reduced seedling susceptibility. Subsequent tests involving spotted (Diabrotica undecimpunctata howardi Barber), striped [Acalymma vittata (Fabricius)], and banded beetles on leaf disks of several C. melo cultivare showed that homozygous double recessive, bibi cblcbl, plants were more resistant to all 3 species of cucumber beetles than nonbitter, bibi Cbl — and bitter Bi—Cbl— plants. This double-recessive resistance provides muskmelon breeders with germplasm which can be incorporated into breeding lines and hybrids.
, ‘Marketmore 97’ contains low levels of cucurbitacins that make it susceptible to spider mites but a poor host for cucumber beetles ( Acalymma vittatum Fab. and Diabrotica undecimpunctata howardi Barber). ‘Marketmore 97F’ is a gynoecious near-isogenic line
mechanisms of maize against pink stem borer Crop Sci. 38 1159 1163 Cardona, C. Gonzalez, R. Schoonhoven, A.V. 1982 Evaluation of damage to common beans by larvae and adults of Diabrotica balteata and Cerotoma facialis J. Econ. Entomol. 75 324 327 Da Costa
Abstract
Resistance to the spotted cucumber beetle, Diabrotica undecimpunctata howardi Barber, the western striped cucumber beetle, Acalymma vittata (Fabricius) and the banded cucumber beetle, Diabrotica balteata LeConte was studied in “near isogenic populations” of cucumbers for the Bi locus. These 3 insects reacted similarly to cucurbitacins in cucumbers but in vitro studies indicated differences in other cucurbits. Bacterial wilt desease was less severe in non-bitter than bitter cucumbers.
Abstract
‘Mainstream’ is a high yielding, small-fruited muskmelon (cantaloupe), Cucumis melo L. weigh 1.1-1.4 kg, have good keeping quality, a pleasing sweet taste, and are high in Vitamin C. The plants are compact and resistant to powdery mildew (Sphaerotheca fuliginea (Schlecht. ex Fr.) Poll.), downy mildew (Pseudoperonospora cubensis (Berk. & Curt.) Rostow., and cucumber beetles (Diabrotica undecimpunctata howardi Barber, Acalymma vittata (Fabricius), and Diabrotica balteata LeConte.
( Diabrotica balteata and Diabrotica undecimpunctata howardi ), and flea beetles ( Systena sp.) ( Chalfant et al., 1990 ; Cuthbert and Davis, 1970 ). Two species of white grubs ( Plectris aliena and Phyllophaga ephilida ), sweetpotato flea beetle
Abstract
Spotted and striped cucumber beetles (Diabrotica undecimpunctata howardi Barber and Acalymma vittata Fab., respectively) caused significantly more damage to bitter cucumber (Cucumis sativus L.) wilted by drought or infection by Erwinia tracheiphila E.F.S.-Holland than to bitter non-wilted or non-bitter wilted and non-wilted plants. Bitter wilted plants had significantly more cucurbitacin than did bitter non-wilted material.
Abstract
Root injury of sweet potato (Ipomoea batatas (L.) Lam) was significantly increased when eggs of banded cucumber beetles (Diabrotica balteata (LeConte)) in a agar-water mixture were applied at preroot enlargement. This technique should prove useful in screening sweet-potato lines or cultivars for insect resistance.
( Diabrotica undecimpunctata howardi ), and squash bug ( Anasa tristis ) ( Bruton et al. 2003 ; Saalau Rojas et al. 2015 ). In addition to causing feeding damage and seedling mortality, cucumber beetles vector the bacterium Erwinia tracheiphila , the causal