…similar places. There, they build an especially strong cocoon that protects them during diapause and pupation. The first adults appear in the spring when the vines develop their first leaves. Two or three days after mating, oviposition begins. The economic injury caused by the first generation is generally moderate, as most varieties of grapevine are able to compensate for the loss of flowers to a certain degree. Much more important is the damage to developing or ripe grapes, not least…
…has shown varying levels of resistance to organophosphates, carbamates and synthetic pyrethroids (Barber et al. 1999). Resistance to pirimicarb was shown to be mainly due to a decreased sensitivity of the target acetylcholinesterase; this modification conferred also, resistance to propoxur but not to methomyl and the two tested organophosphates (acephate and paraoxon). Endosulfan resistance was associated with a moderate level of resistance to dieldrin, and resistance to both insecticides was due, in part, to increased detoxification by glutathione S-transferases (GST)…
…falling temperatures or crowding), winged forms appear and start to colonize other plants. In warm weather, the generation cycle can be completed in about a week; each female is able to produce 60-80 larvae during its reproductive period of 3-4 weeks. Accordingly, population growth can be very rapid. In climates with mild winters, parthenogenesis remains the only mode of reproduction throughout the year. In colder regions, however, sexual forms appear in the autumn, which then migrate to the primary (winter)…
The fall armyworm is a highly polyphagous migratory lepidopteran pest species. It can colonize over 80 different plant species including many grasses, and crops such as alfalfa, soybean, sorghum, and corn. Eggs are laid in clusters of 50 or more in a single layer attached to foliage. Newly hatched larvae are pale green with black heads and during the second instar the head turns an orange-brown color. Fully grown larvae are 1.25 – 1.5 inches in length and vary…
Known as Indian cotton jassid, Indian cotton leafhopper, green jassid, cotton leafhopper or okra leafhopper, this is a hemipterous pest commonly found in India and that attacks plants of at least 25 species such as potatoes, beans, sorghum, maize, cotton and okra. In cotton, yield losses may be as high as 100-114 kg of fiber per hectare and in sunflowers attack combined with whiteflies may result in losses of 9.2%. Eggs are yellowish-white, curved and measure 0.73 x 0.24…
T. vaporariorum probably has the most comprehensive host range of all insect pests. It includes about 800 species. Besides vegetables, the most threatened crops in glasshouses are ornamentals. T. vaporariorum originates from Central America, but is nowadays found worldwide. The adults live about 3-6 weeks, during which time each female may lay several hundred eggs. Reproduction is almost always parthenogenetic. Under favorable conditions, the whole life cycle can be completed in 3-4 weeks. The nymphs and adults of whitefly…
Adults are up to 3 mm in length. The body colour is determined partly genetically, and partly by the environment (especially food quality). Most clones tend to be yellowish to dark green or brown, or sometimes orange-pink. The species spends its entire year on cereals and grasses. Only a small proportion of the population overwinters as eggs on Gramineae, and these hatch in early spring. The majority of the population overwinters as mobile stages on wild grasses or winter cereals…
Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is one of the world’s top 100 invasive organisms found on over 900 host plants all around the world. It is currently recognized as a complex of cryptic species with world wide distribution. The two most important phylogenetic groups of B. tabaci from an agricultural perspective are MEAM1 (Middle East-Asia Minor 1; also commonly known as biotype B) and MED (Mediterranean; including the commonly known biotype Q among others). It reportedly transmits over a…
Diaphorina Citri is the insect vector associated with the transmission of the bacteria Candidatus Liberobacter asiaticus and Can. L. americanus. These bacteria are considered to be the causal agents of Huanglongbing (HLB) in Asia and Americas. Trees infected with the bacterial pathogen begin to show symptoms such as early fruit drop and mottled leaves anywhere from 5 months to 3 years after infection. Even during this asymptomatic period, plants can also be source of inoculum, hence the importance to manage…
Aphis gossypii Glover (Hemiptera: Aphididae) is a destructive pest of numerous crops worldwide. This sap-sucking insect affects plants via direct feeding and indirectly via plant viral disease transmission (more than 50 plant pathogenic viruses known). It has a very wide host range with at least 700 host plants being known world-wide. It can seriously affect most cucurbit and solanaceous vegetable crops as well as leafy vegetables, legumes, potato, ornamentals, stone fruits, oil seed rape, citrus, cotton or many other…