Pests in the vegetable garden in September and October

The forecast minimum temperature values are above the critical levels for vegetable crops, which is a prerequisite for obtaining additional vegetable production from late field cultivation.

Pests

Tomato leafminer moth

It continues to damage tomatoes

Species – Tuta absoluta

Damage

• The larvae cause the damage;
• They prefer the leaves and stems of the plants, but also attack the fruits;
• The damage appears as short and wide mines on the leaves, in which larvae and excrement can be seen;
• On the fruits, mines are observed, which serve as an entry point for the development of rot processes;
• It causes significant losses of the tomato yield, with damage reaching up to 100%.

Development

• The moths are active at night and hide during the day;
• The larvae cause the damage;
• Depending on environmental conditions, it can develop 10-12 generations per year;
• The species overwinters as egg, pupa or adult in the soil, in plant residues or in other shelters.

Control

Use of pheromone traps for monitoring and reducing population density;

• Placement of black sticky traps;
• At low population density in greenhouses, one of the biological control agents Macrolophus pygmaeus or Nesidiocoris tenuis may be introduced;
• Treatment with plant protection products (PPP) upon appearance;
• Economic threshold in greenhouses: larvae – 10% of the leaves with mines; 4% of the fruits damaged;
• Authorized PPP: Avant 150 EC 25 ml/da; Alverde 240 SC 100 ml/da; Altacor 35 WG 8-12 g/da; Ampligo 150 ZC 40 ml/da; Affirm 095 SG 150 g/da; Bermektin 50-100 ml/da;  Voliam Targo 063 SC 0.08%; Confidor Energy OD 80 ml/da; Coragen 20 SC 14-20 ml/da; Exalt 200-240 ml/da; Lanat 20 SL 125 ml/da; Lanat 25 WP 100 g/da; Minecto Alpha 100 ml/da; Mospilan 20 SP  0.02%; Nim Azal T/C 0.3%; Picador 20 SL 0.05%; Rapax SBS 100-200 ml/da; Sineis 480 SC 10-25 ml/da; Warrant 20 SL 50 g/da.

Due to intensive harvesting during the period, PPP with a shorter pre-harvest interval should be selected.

Thrips: tobacco thrips and western flower thrips

Species – Thrips tabaci and Frankliniella occidentalis

Damage

• On the leaves, petioles, flowers and fruits, small whitish spots with dark dots appear – the pest’s excrement;
• At higher population density the spots merge;
• The generative organs of plants attacked in the early stages of development dry up and fall off;
• They are vectors of tomato spotted wilt virus (bronzing).

Development

• Mainly on the leaves, less often on the flowers;
• They develop at high temperatures and low air humidity;
• The western flower thrips mainly attacks the flowers;
• After feeding, the larvae enter the soil and at a depth of about 5 cm they transform into nymphs;
• During one growing season 6-7 generations can develop, and under greenhouse conditions the pest occurs year-round;
• They overwinter as adults or as larvae of different ages in plant residues of infested plants, on weeds and in the soil.

Control

• Regular field inspections;
• Placement of blue sticky boards;
• Immediate treatment with PPP upon appearance;
• Economic thresholds:

Tomatoes in greenhouses – western flower thrips: adults 1 per flower; tobacco thrips – adults and larvae 3 per leaf;

Peppers – flowering: adults and larvae 2 per flower; fruiting: 3 per fruit;

Eggplant – flowering: adults and larvae 2 per flower; fruiting: 3 per fruit;

Cucumbers – during vegetation: adults and larvae 1 per flower, 3-5 per leaf;

• Authorized PPP: Exalt 200-240 ml/da; Deka EC / Desha EC / Dena EC / Poleci / Decision 30 ml/da; Dicarzol 10 SP 556 g/da; Lanat 25 WP 80-100 g/da; Meteor  0.06-0.07%; Minecto Alpha 100 ml/da; Naturalis 100-150 ml/da; Oikos 100-150 ml/da; Sineis 480 SC 10-37.5 ml/da; Requiem Prime 500-1000 ml/da; Limocid 400-800 ml/da.

Due to intensive harvesting during the period, PPP with a shorter pre-harvest interval should be selected.

Two-spotted spider mite

Hot and dry weather is a prerequisite for severe infestation

Species – Tetranychus urticae

Damage

• They live and feed on the underside of the leaves;
• At the feeding site a light, pinpoint spot is formed;
• Under heavy infestation the leaves are covered with webbing;
• Later the spots merge and the leaf becomes marbled;
• Under severe infestation the plants dry out.

Development

• The mites prefer older leaves with reduced water content, as well as drought-stressed, senescent plants;
• In greenhouses they develop continuously.

Control

• Destruction of weeds in and around the crops;
• Maintaining optimal soil moisture;
• Regular inspection of crops for early detection of mite infestation;
• Treatment with PPP upon appearance;
• Economic thresholds:

Tomatoes: flowering-fruiting, larvae–adults 5-10% infested plants;

Peppers: during vegetation, larvae-adults 5-6 per leaf;

Cucumbers: during vegetation, larvae-adults 5-10% infested plants;

• Authorized PPP: Apollo 50 SC 30-40 ml/da; Apache EW 30-100 ml/da; Akramite 480 SC 20-25 ml/da; Boutique 30-100 ml/da; Bermektin 15-100 ml/da; Vertimec 018 EC 60 ml/da; Valmek 15-100 ml/da; Voliam Targo 80 ml/da; Zoom 11 SC 30-35 ml/da; Laota 15-100 ml/da; Masai WP 15-25 g/da; Nelta SC 100 ml/da; Nissorun 10 WP 50-75 g/da; Nim Azal 0.3%; Danitron SC 100-200  ml/da; Requiem Prime 500-1000 ml/da; Sulphur WG 300 g/da; Thiovit Jet 80 WG 300 g/da; Floramite 240 SC 40 ml/da; Naturalis 100-200 ml/da.

Due to intensive harvesting during the period, PPP with a shorter pre-harvest interval should be selected.

Cotton bollworm

It continues to damage tomatoes and peppers

Species – Helicoverpa armigera

Damage

• Initially the larvae gnaw the leaves, buds and flowers;
• Later they attack the fruits, bore into them and feed on their contents;
• Damaged fruits do not grow, become deformed and rot due to secondary pathogens.

Development

• It overwinters as a pupa in the soil;
• It develops three generations per year;
• Adults occur from May to October;
• Fecundity depends on air temperature and humidity, on the availability of nectar for sexual maturation of the moths and on the plants on which the larvae feed;
• The greatest damage to vegetable crops is caused by larvae of the second generation.

Control

• Regular field inspections;
• Use of pheromone traps for monitoring;
• Destruction of weed vegetation in and around the crops;
• Treatment with PPP is effective when targeted against young larvae;
• Economic thresholds:

Tomatoes: fruit set, larvae 5% damaged fruits;

Peppers: fruit set, larvae 3-5% damaged fruits;

• Two treatments are necessary at an interval of 8-10 days, depending on weather conditions and the residual effect of the insecticide;
• The egg parasitoid Trichogramma spp. can also be used for pest control;
• Authorized PPP: Avant 150 EC 25 ml/da; Altacor 35 WG 8-12 g/da; Ampligo 150 ZC 40 ml/da; Affirm 095 SG 150 g/da; Vaztak New 100 EC 10 ml/da; Voliam Targo 80 ml/da; Deltagri 30-50 ml/da; Decis 100 EC 7.5-12.5 ml/da; Infis 50 ml/da; Exalt 200-240 ml/da; Coragen 20 SC 14-20 ml/da; Lanat 25 WP 80-100 g/da; Lanat 20 SL 125 ml/da; Oikos 100-150 ml/da; Minecto Alpha 100 ml/da; Rapax 100-200 ml/da; Citrin Max 10 ml/da; Helicoverex 20  ml/da.
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• Cabbage moth

Species – Mamestra brassicae

Damage

• The larvae cause feeding damage on the leaves and cabbage heads;
• After hatching, the larvae live on the underside of the leaves; later they eat the leaves leaving only the thick veins and then bore into the cabbage head;

Damaged cabbage heads have an unpleasant odor.

Development

• It develops two to three generations per year;
• It overwinters as a pupa in the soil.

Control

• Regular inspections of transplanted plants;
• Treatment with PPP upon detection of infestation;
• Economic thresholds:

Late production, larvae  15-18 per 100 plants;

• Authorized PPP: Avant 150 EC 17 ml/da; Altacor WG 8-10 g/da; Karate Zeon 5 CS 15 ml/da; Deka EC / Desha EC / Dena EC / Poleci / Decision 30 ml/da; Decis 100 EC 12.5 ml/da; Dukat 25 EC 30 ml/da; Meteor 60-70 ml/100 l water; Sumi Alpha 5 EC / Sumicidin 5 EC / Oasis 5 EC  25 ml/da; Dipel 2 X 100 g/da.

An adjuvant should be added to the spray solution.

Diamondback moth

Species – Plutella maculipennis

Damage

• The larvae cause damage already at the seedling stage. They bore under the epidermis and mine the leaves;
• Older larvae damage the outer and inner leaves of the cabbage head and subsequently the heads remain small and deformed.

Development

• It develops four to six generations per year;
• It overwinters as a pupa on plant residues and under soil clods.

Control

• Regular inspections of transplanted plants;
• Treatment with PPP upon detection of infestation;
• Economic threshold: after head formation, larvae causing 10% damaged leaf mass;
• Authorized PPP: Altacor WG 8-10 g/da; Vaztak New 100 EC 10 ml/da; Deka EC / Desha EC / Dena EC / Poleci / Decision 50 ml/da; Meteor 80-90 ml/100 l water; Mageos 7 g/da; Sumi Alpha 5 EC / Sumicidin 5 EC / Oasis 5 EC  25 ml/da.

An adjuvant should be added to the spray solution.

Large and small white butterflies of cabbage

Species – Pieris brassicae and Pieris rapae

Damage

• Young larvae live together up to the second instar. They gnaw the leaves without affecting the upper epidermis;
• Older larvae eat the leaves completely, together with the thin veins, skeletonizing them and leaving only the thick veins.

Control

• Regular inspections of transplanted plants;
• Treatment with PPP upon detection of infestation;
• Economic thresholds: after transplanting the crop, when more than 1% of the plants are heavily infested or 2-3 larvae/plant are found. In later stages – egg clusters on 5% of the plants or 25% damaged leaves from larvae;
• Authorized PPP: Avant 150 EC 17 ml/da; Altacor WG 8-10 g/da; Vaztak New 100 EC 10 ml/da; Dipel 2 X 100 g/da; Dukat 25 EC 30 ml/da; Mageos 7 g/da; Meteor 60-70 ml/100 l water.

An adjuvant should be added to the spray solution.