Greenhouse Pest Management AR Flashcards
Study into percentage of pest induced crop damage
Yang et al., 2014 - whiteflies, aphid, thrips and spider mites cause 18% production loss in greenhouse vegetables
Key points B.tabaci
Damages via feeding, honeydew and virus spread Management methods include biocontrol using parasites such as Eretmocerus, predators such as lacewings and fungi such as Beauveria bassiana Important to identify the specific species of whitefly to employ appropriate management techniques
Study into B.tabaci biocontrol predators and parasitoids
Hoelmer et al., 1994 - Predatory beetle Delphastus pusilus feeds on all stages of B.tabaci - Shows a tendency to avoid whiteflies parasitised with 3rd and pupal Eretmocerus spp. - Thought to be due to parasite induced cuticular hardening
Study into B.tabaci fungi biocontrol
Wraight et al., 1998 -B.bassiana effective in reducing third and fourth instar of whitefly on greenhouse vegetables by more than 90%
Study into B.tabaci oils
Aslan et al., 2003 - Resistant to almost all classes of insecticides as a result of overuse on cotton crops - essential oils from plants a useful technique, especially in greenhouses as they can be applied as fumigants - Findings from study show high efficacy against the adults of B.tabaci and to the nymphs and adults of T.urticae - Essential oil of Satureja hortensis most efficient, 1.563microliters air dose required for 100% mortality rate after 96h
Study into B.tabaci host plant resistance
Zaidi et al., 2017 - Expression of insecticidal proteins and/or toxins or double stranded RNA (dsRNA) homologous to B.tabaci genes shown to provide plant with protection to B.tabaci and the begomoviruses it transmits
Key points M.persicae
Damages via feeding, honeydew and viruses Management - early treatment, bocontrol and biorationale insecticides
Study into M.persicae biocontrol
Mohammed and Hatcher, 2017 - Simultaneous applications of parasitoid Aphidius colemani and fungus Lecanicillium muscarium - Much more effective in conjunction with each other - Results 7 weeks post treatment Treatment Aphids/Leaf Control (No biocontrol) 130 Lm only 60 Ac only 35 Lm+Ac 15
Study into M.persicae neem
Shannag et al., 2014 - Neem oil: 2 applications, 7 days apart = almost total eradication - Neem based oils - highly effective at surpressing aphid population (50-75% of controls) but inefective as a repellent
Key points F.occidentallis
Damages via feeding and viruses Management - use of indicator plants, removal of weeds in and around greenhouses, biocontrol, insecticide treatment early in the morning or evening as this is when adults are most active
Study into F.occidentallis weeds
Macharia et al., 2016 - weeds support thrips reproduction but also act as a host to vurses that can affect greenhouse crops (e.g. tomato spotted wilt virus)
Study into F.occidentallis fungus
Ugine et al., 2006 - Fungal pathogens (B.bassianna) only reduced the population by 30-40% and thus are not potent enough to stop population growth - may be effective in conjunction with other controls
Study into F.occidentalis biocontrol
Saito and Brownbridge, 2016
Tretaments comparing single use of predators, fungi, and nematodes against use of multiple
Predators - Dalatia sp., Stratiolaelaps sp., Gaeolaelaps sp.
Fungi - Metarhizium brunnem (MET52), B.bassiana (BG)
Nematodes - Stenernema spp.
Results
- D 52%, M 65%, B 13%, D+M 90%, D+B 70%
- S 77%, M 35%, B 25%, S+M 90%, S+B 92%
- G 74%, M 35%, B 33%, G+M 84%, G+B 88%
Nematodes not effective in conjunction
Key points T.urticae
Damages via feeding Management - good sanitation, spraying during winter (overwinter in greenhouses), biocontrol at low populations, mitecides
Study into T.urticae biocontrol
Opit et al., 2004 - Control by Phytoseiolus persimilus can be achieved at relatively low predator:prey ratio (1:20) - Most effective at 1:4 though, after four weeks at 1:4 aphids per leaf declined from 30 to <0.6
