How to identify and control tomato Fusarium wilt and bacterial wilt?

Tomato Fusarium wilt and bacterial wilt are extremely important diseases constraining summer and autumn tomato production in our region, causing huge losses to growers. Under normal circumstances, these two diseases are easily confused when being identified. Their common symptom is wilting, but the two are different, so their control measures have similarities as well as differences. The key techniques for identifying and controlling these two diseases are introduced below.

I. Differences
1. Bacterial wilt affects the whole plant, and seedlings show no symptoms, whereas Fusarium wilt can occur at the seedling stage. In bacterial wilt, the top leaves wilt first, whereas in Fusarium wilt, the leaves develop symptoms gradually from the bottom upward.
2. In bacterial wilt, the diseased leaves wilt and droop without losing their green color, whereas in Fusarium wilt, the diseased leaves turn from green to yellow, and there is also the phenomenon of one half dying while the other half is still alive.
3. The speed of disease development differs. Bacterial wilt develops relatively quickly and causes death in just a few days. Fusarium wilt, however, develops slowly and takes about 15 to 30 days to cause death.
4. In bacterial wilt, during damp weather, when the diseased stem is cut crosswise and squeezed, a milky white slime oozes out. In Fusarium wilt, during damp weather, pink mold grows at the base of the stem, whereas bacterial wilt does not have this.
5. Bacterial wilt is a bacterial disease, whereas Fusarium wilt is a fungal disease.

II. Control
1. Agricultural control The agricultural control measures for tomato bacterial wilt and Fusarium wilt are basically the same.
(1) Selecting disease-resistant varieties suitable for local planting is helpful for controlling the occurrence, development and spread of the diseases. Through trial demonstrations, tomato varieties such as Kangqing 19, Danfen No. 1, Fengbao, Hongkang No. 1, Xiaxing and L402 have good resistance to bacterial wilt. At present, there is still no very good disease-resistant variety for Fusarium wilt, but grafted cultivation can be used to control the occurrence of this disease, using the wild tomato CH-Z-26 as the rootstock for grafting.
(2) Field and greenhouse management need to be strengthened, with deep furrows and high beds for planting, avoiding waterlogging in the field that damages roots and uneven wetting and drying; promptly remove diseased plant residues from the field to avoid causing greater spread of the pathogen.
(3) Apply sufficient base fertilizer, preferably dry chicken manure compound fertilizer that has been treated at high temperature, increase the application of phosphorus and potassium fertilizers, and spray foliar fertilizers such as Nonglebao and Aopuer 2 to 3 times during the growing period, which is helpful for improving plant resistance. Pay attention to controlling underground pests and nematodes.
(4) For fields with relatively severe disease, a 4 to 5 year rotation can be carried out with onions, garlic and cruciferous vegetables.
2. Chemical prevention
(1) For bacterial wilt, use soilless or new soil seedling raising; at transplanting, carry out chemical root drenching or root soaking; before transplanting, use 77% Keshade 500 times solution for root drenching, or use agricultural streptomycin sulfate 3000 to 4000 times solution for root soaking for 1 to 2 hours.
(2) For Fusarium wilt, use soilless or new soil seedling raising or seedbed soil disinfection, using 8 to 10 grams of 50% carbendazim wettable powder per square meter of bed surface, mixed evenly with 4 to 5 kilograms of fine soil, first spreading 1/3 of the medicated soil on the bed surface, then sowing, and then covering the seeds with the remaining medicated soil; at transplanting, carry out chemical root drenching or root soaking. 1 to 2 days before transplanting, use 50% carbendazim 500 times solution for root drenching, or use 50% carbendazim 500 times solution for root soaking for 1 to 2 hours.
3. Chemical control
(1) For bacterial wilt, when diseased plants are found in the field, they should be immediately pulled up and burned, and the surrounding soil should be disinfected; use 2% formalin solution or 20% lime water for disinfection; in the early stage of disease, use 77% Keshade 400 times solution or agricultural streptomycin sulfate 3000 to 4000 times solution, or 25% copper ammonia complex 500 times solution for root drenching, 300 to 500 grams per plant; when diseased plants in the field reach more than 80% and there is no value for production management, destroy the crop.
(2) For Fusarium wilt, when diseased plants are found in the field, immediately pull them up and burn them, and disinfect the surrounding soil; drench with 50% carbendazim 500 times solution or 70% thiophanate-methyl 500 times solution; in the early stage of disease, use 50% carbendazim 500 times solution or 70% thiophanate-methyl 500 times solution for root drenching, applying 250 grams of chemical solution per plant; when diseased plants in the field reach more than 80% and there is no production value, destroy the crop.